Download Fleeming Jenkin and "The Origin of Species"

The British Society for the History of Science
Fleeming Jenkin and "The Origin of Species": A Reassessment
Author(s): Susan W. Morris
Source: The British Journal for the History of Science, Vol. 27, No. 3 (Sep., 1994), pp. 313-343
Published by: Cambridge University Press on behalf of The British Society for the History
of Science
Stable URL: http://www.jstor.org/stable/4027601
Accessed: 11/10/2009 01:29
Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at
http://www.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms and Conditions of Use provides, in part, that unless
you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you
may use content in the JSTOR archive only for your personal, non-commercial use.
Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at
http://www.jstor.org/action/showPublisher?publisherCode=cup.
Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed
page of such transmission.
JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of
content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms
of scholarship. For more information about JSTOR, please contact [email protected].
Cambridge University Press and The British Society for the History of Science are collaborating with JSTOR to
digitize, preserve and extend access to The British Journal for the History of Science.
http://www.jstor.org
BJHS, 1994, 27, 313-43
Fleeming Jenkin and The Origin of Species: a
reassessment
SUSAN
W. MORRIS-
INTRODUCTION
Early in June of 1867, Charles Darwin turned back the cover of his copy of the respected
quarterlyNorth British Review, to find on its opening pages a lengthy essay attacking his
theory of natural selection.1 As with the vast majority of articles in the Victorian
periodicals, the review was anonymous,2 prompting immediate speculation in Darwin's
circle as to the author's identity. It was to be about a year-and-a-halfbefore Darwin would
learn that the engineer Fleeming Jenkin had written the essay. By then, Darwin had
concluded that the critique was the most valuable he had ever read on The Origin of
Species.
The traditional interpretation of Jenkin's value to Darwin has been that he altered
Darwin's views on two related problems: that of what were termed 'individual differences'
versus 'single variations', and on a problem known as the 'swamping' of variation by
'blending inheritance'.' In the nineteenth century, inheritedtraits were held to derive from
the differingtraits of the parents having been 'blended' together. 'Individual differences',
for Darwin, were the ordinary characteristicsby which we recognize any one individual
from among all the others in its species. 'Single variations', by contrast, referred to
unusual, discontinuous mutations, also known as saltations or sports. Jenkin was thought
to have demonstrated to Darwin that single variations, being rare, would be 'swamped'
out of existence by the 'blending' of their traits when they bred back into the large, general
population of unvaried creatures. The persuasiveness of Jenkin's argument, scholars
> Department of the History of Science, Medicine & Technology, The Johns Hopkins University, Baltimore,
Md 21218, USA.
I wish to thank Bruce Hunt, John Brooke and two referees for useful criticisms and suggestions. I am
particularly indebted to the valuable insight and advice of Sharon Kingsland.
1 'The Origin of Species', North British Review (hereafterNBR) (June 1867), no. 92, 46 o.s., 7 n.s., 277-318
(Americanedn, pp. 149-71). Reprinted (as 'Darwin and the Origin of Species') in H. C. Fleeming Jenkin, Papers
Literary, Scientific, etc. (hereafterPLS; ed. S. Colvin and J. A. Ewing), 2 vols., London, 1887, i, 215-63, and in
D. L. Hull (ed.), Darwin and His Critics, Cambridge, Mass., 1973, 302-44.
2 W. E. Houghton estimates that '85 to 90%' of all review articles were anonymous. See Houghton, "'The
Wellesley Index": uses and problems', The Victorian Periodicals Newsletter (1968), 1, 13.
3 For examples of this traditional interpretation,see E. B. Poulton, Essays on Evolution, 1889-1907, Oxford,
1908; J. C. Willis, The Course of Evolution, Cambridge, 1940; L. C. Eiseley, Darwin's Century: Evolution and
the Men Who Discovered It, Garden City, 1958; G. Hardin, Nature and Man's Fate, New York and Toronto,
1959.
14-2
314
Susan W. Morris
believed, drove Darwin to greater reliance on Lamarckismand on mechanisms other than
natural selection to account for evolution.4
In 1963, Peter Vorzimmer and a number of other historians began pointing out errors
in this conventional interpretation.5Even their work, however, unfortunately shares with
the orthodox interpretation many misreadings of what Jenkin said, and how Darwin
reacted. This paper reassessesJenkin, his review, and Darwin's response, proposing a new
explanation of how and why Jenkin influenced Darwin.
Perhaps the most significant misreading lies in identifying Jenkin's principal argument.
The present paper argues that Jenkin's main point was on the shortness of geological time
(the age of the earth) and, though historians sail in troubled seas when dealing with
historical influence, proposes that Darwin, too, regarded geological time as the essay's
most important argument. In contrast, most commentators have consistently asserted that
Jenkin's main point deals with variations and inheritance. This view arises, I believe, for
two reasons. One is that the swamping argument was, indeed, perceived by many
naturalists of the time to be a major obstacle to incrementalevolution, spawning a whole
school of isolation theories in response. For those theorists the essay's swamping argument
was a crucial obstacle to natural selection, and many later scholars have inferred that
Darwin shared this view. Secondly, some authors have been predisposed, by their
recognition of the later importance of Mendelism, to see the issue of heredity as presenting
a decisive problem for evolutionary theories; they consequently award great importance to
arguments,such as Jenkin's, dealing with inheritance.Accordingly, they have also misread
Darwin's reaction to Jenkin's essay, seeing in Darwin's shift to Lamarckism a direct
response to problems of heredity. Yet Darwin's shift can be interpretedas an attempt to
acceleratethe pace of evolution in order to overcome a newly recognizedshortness of time.
Scholars have largely overlooked the fact that Darwin's reading of Jenkin's review marks
the onset of Darwin's troubles over the dilemma of geological time.
ORIGIN AND ANALYSIS OF THE TRADITIONAL
INTERPRETATION
Despite the widespread belief that there is ample evidence that Jenkin influenced Darwin
in the matter of variations, actual evidence has always been scanty. Indeed, the traditional
interpretation of Jenkin's influence relies almost wholly on two letters from Darwin to
Alfred Russel Wallace in early 1869, in which Darwin noted, 'Fleming Jenkyn's [sic]
4 While Darwin's natural selection rested primarilyon the mechanismof small, continuous change, the extent
of his reliance on other, larger mechanisms of change was ambiguous. P. Bowler, in 'Darwin's concepts of
variation', Journal of the History of Medicine (1974), 29, 196-212, discusses this ambiguity, advancing the idea
that Darwin entertained, in addition to single variations and individual differences,a 'third concept' of variation,
namely small but discontinuous changes. For Darwin's reliance on sexual selection, see H. Cronin, The Ant and
the Peacock: Altruism and Sexual Selection from Darwin to Today, Cambridge, 1991.
5 See, for example, P. Vorzimmer, 'Charles Darwin and blending inheritance', Isis (1963), 54, 371-90;
reprintedin P. Vorzimmer, CharlesDarwin: The Years of Controversy,Philadelphia,1970; R. C. Olby, 'Charles
Darwin's manuscript of pangenesis', BJHS (1963), 1, 251-63; G. L. Geison, 'Darwin and heredity: the evolution
of his hypothesis of pangenesis', Journal of the History of Medicine (1969), 24, 375-411; J. D. Burchfield,
'Darwin and the dilemma of geological time', Isis (1974), 65, 301-21.
Fleeming Jenkin and The Origin of Species
315
arguments have convinced me' and 'F. Jenkins [sic]argued... against single variations ever
being perpetuated and has convinced me.'6 It is easy to combine these two statements with
changes appearing in the subsequent edition of the Originof Species(fifth edition, August
1869), in which Darwin specifically mentioned Jenkin's article, and to infer that Jenkin's
criticisms on variations and swamping decisively engendered Darwin's changes.
Peter Vorzimmer was the first to demonstrate the misleading nature of this superficial
interpretation of Jenkin's influenceon Darwin. Citing evidence from Darwin's notebooks,
from the 'Essay of 1844' and particularlyfrom the Variation of Animals and Plants under
Domestication, all written before Jenkin's article appeared,Vorzimmerdemonstratedthat
the changes appearing in the fifth edition of the Origin expressed ideas Darwin had long
held. This impressive argument, supported by Olby's 1963 publication of Darwin's
manuscript on 'Pangenesis', and by more recent work by Geison, demonstratedthat, with
respect to Darwin's views on inheritance and variation, Jenkin's article could not have
done more than convince Darwin of the correctness of conclusions that he had already
reached on his own.7
We cannot doubt, however, that Jenkin's essay had an important effect on Darwin. For
example, Darwin wrote to J. D. Hooker that, 'Fleming Jenkyns [essay] has given me much
trouble, but has been of more real use to me than any other', and FrancisDarwin observed
that 'my father ... felt [Jenkin'scriticisms]to be the most valuable ever made on his views'.8
Scholars have assumed that these two statements refer to variations and inheritance.
Indeed, they are generally adduced as part of the 'ample evidence' supporting the
traditional interpretation of Jenkin's role. A moment's reflection, however, makes us
realize that these statements do not link Jenkin's essay with any specific area of Darwin's
theory. Linking them to variations and inheritanceis a convention, which does not appear
to be supported by the evidence.9
Vorzimmer'spaper, therefore, by the very process of demonstratingthat Darwin was not
notably influenced by Jenkin in the matter of variations, effectively creates a new puzzle:
if Jenkin's essay was indeed as inconsequential as Vorzimmer suggests, what could have
led Darwin to conclude that the review was so valuable? The present paper suggests that
Darwin had in mind Jenkin's argument on geological time.
In the nineteenth century, there were two great problems that barredfull acceptance of
the emerging ideas of evolution: one was the nature of heredity; the second was a genuine
doubt that the earth was sufficientlyold for a slow evolutionary scheme such as Darwin's
to have worked. With the onset of the twentieth century, the introduction of Mendelism
6 Darwin to Wallace, 22 January1869 and 2 February1869, British Library(hereafterBL) Add 46434. See also
F. Burkhardt, S. Smith et al. (eds.), A Calendar of the Correspondence of Charles Darwin, 1821-1882, with
Supplement, Cambridge, 1994, which lists the published sources and the known archive of each letter.
7 Olby, op. cit. (5); Geison, op. cit. (5); Vorzimmer, op. cit. (5), 389.
8 Darwin to J. D. Hooker, 16 January 1869, CambridgeUniversity Library,Darwin Archive (hereafterDAR),
94:112-13; F. Darwin (ed.), The Life and Letters of Charles Darwin, 2 vols., New York, 1959, ii, 288-9.
9 Typical examples of this linkage can be seen in Willis, op. cit. (3), 5, who writes 'the variation would soon
tend to be lost by crossing. This was shown by Fleeming Jenkin in a criticism which Darwin considered as the
best that was ever made of his work.' And Eiseley, op.cit. (3), 209-10, in discussing Darwin's views on variations,
says, 'there is ample testimony... to the effect which Jenkin's criticism had upon him', and then cites as that
testimony the letters to Wallace as well as that to Hooker; this latter, as just noted, says nothing about variations.
316
Susan W. Morris
greatly facilitated the understandingof heredity, hence of evolutionary theory; as a result
considerable attention has been focused on the historical development of inheritance
theories. By contrast, the discovery, at roughly the same time, that the earth's heat was
constantly generated by radioactive decay, restored to naturalists the 'countless ages'
needed for gradual evolution, and thus allowed questions about the age of the earth to
evaporate as an obstacle for evolutionary theorists. The interest of historians in the
question appeared to have evaporated with it, until Stephen Brush and Joe Burchfield
reminded scholars that the earth's age always remained a deeply significant quandary for
Darwin.10Burchfieldsuggested, moreover, that Darwin's inability to devise a satisfactory
counter-argumentallowed historians to undervaluea problem Darwin himself regardedas
the 'gravest' objection ever raised against his theory.11
In other words, when the shortness-of-timethreat dissipated, Jenkin's criticisms on this
point came to appear superfluous. Consequently, with the question of geological time
declining in historical importance, and interest in heredity increasing, Jenkin's essay, and
its influence on Darwin, came to be treated within the framework of Mendelian
enlightenment, casting the rest of Jenkin's review into the shadows.12One has only to note
how universallyJenkin's article is describedas having only two arguments- the swamping
from blending inheritance, and the limits to variation - to realize how narrowly his article
has been assessed.13In truth, the article makes five separate arguments against natural
selection: on the limits to variation, the swamping of variations by large numbers, the
shortness of geological time, the problems of classification, and the logical rigour of
Darwin's theory.
The traditional interpretationof Jenkin's essay appears to begin with St George Jackson
Mivart, in his 1871 On the Genesis of Species. In advancing his own ideas in opposition
to Darwin's, Mivart made extensive use of Jenkin's essay. His characterizationof the essay
introduced what became the traditional interpretation of Jenkin's contribution: Mivart
emphasizes the swamping of variations by inter-crossing; he quotes the notorious
10 Burchfield, op. cit. (5). S. G. Brush, 'Science and culture in the nineteenth century: thermodynamics and
history', The Graduate Journal (1966-7), 7, 477-565.
11 C. Darwin, The Origin of Species by Charles Darwin: A Variorum Text (ed. M. Peckham), Philadelphia,
1959, 728.
12 For example, both Poulton, op. cit. (3), and Eiseley, op. cit. (3), embed their discussions of Jenkin's influence
on Darwin within their chapters on Mendel.
13 For example, Vorzimmer,op. cit. (5), 387, says of Jenkin's essay: 'the main attack can be divided into two
distinct halves ... one against individual differences, the other against saltations'. Hull, op.cit. (1), 346, says:
'Jenkin raised two major objections.' P. J. Bowler, in The Eclipse of Darwinism, Baltimore, 1983, discusses only
blending inheritance before noting that Jenkin 'also argued' about limits to variation. Similarly, Hardin, op. cit.
(3), hints at the limits argumentbut focuses on swamping. Eiseley, op. cit. (3), mentions only swamping. J. Moore,
in The Post-Darwinian Controversies, Cambridge, 1979, and M. Ruse, in The Darwinian Revolution, Chicago
and London, 1979, both briefly mention Jenkin's criticisms relating to geological time, but focus on swamping
and limits. Geison, op. cit. (5), and Burchfield,op. cit. (5), and in Lord Kelvin and the Age of the Earth, New York,
1975, both mention Jenkin's argument about geological time, but do not see it as the essay's centrepiece.
Burchfield, for example (Kelvin, p. 73), asserts that Jenkin's review 'hinged' on the swamping argument, and
Geison says Jenkin's 'attack... was directed especially against... heredity', op. cit. (5), 380. C. Smith and M. N.
Wise, Energy and Empire: A Biographical Study of Lord Kelvin, Cambridge, 1989, focus on Jenkin's argument
on geological time. Only S. J. Gould, in 'Fleeming Jenkin revisited', Natural History (1985), 94, 14-20, assesses
Jenkin's full article.
Fleeming Jenkin and The Origin of Species
317
'shipwreck' story (reviewed below), which soon became standard practice for discussions
of Jenkin's work; he cites the limits to variation as Jenkin's second argument; and he
originates the claim that Jenkin's review provoked a change in Darwin's thought by writing
that 'the consideration of [Jenkin's] article has occasioned Mr. Darwin to make an
important modification in his views'.14
Clearly, the close identification of the swamping argument with Jenkin's essay seems to
issue from Mivart. Jenkin, in fact, was not unique in making the swamping criticism
against natural selection, but his review was one of the first to receive much attention.
Appearing, as it did, in 1867, Jenkin's work seemed to have provoked the school of
isolation theories which arose almost immediately thereafter, intended to surmount the
problem of swamping; Moritz Wagner's'Migration Law', published in 1868, was one such
example.15Until the twentieth century and the introduction of Mendelism, the swamping
problem greatly concerned evolutionary theorists (other than Darwin), and Jenkin
continued to receive the greatest credit for introducing it. In 1886, for example, George
Romanes, writing on the 'Difficulties against Natural Selection as a theory' could state
that, 'the third and last difficulty... consists in the swamping influence... [which] was first
prominently announced in an anonymous essay by the late Professor Fleeming Jenkin'.
Romanes went on to describe Jenkin's article as,
a highlyremarkableone... [presenting]
a moresearchingandeffectivecriticismof Mr. Darwin's
theorythananyotheressaywithwhichI amacquainted.Withregardto [swamping],thecriticism
is especiallycogentand, so far as I know,is the only criticismof importancewhichMr. Darwin
has not expresslyanswered.
Romanes then quoted, in a footnote, all of Jenkin's shipwreck story, as a way of giving the
flavour of Jenkin's critique.16
By 1888, swamping was being described as the 'celebrated difficulty' of Darwinian
evolution, 'first forcibly pointed out by the late Professor Fleeming Jenkin'.17 Vernon
Kellogg, in 1907, illustrated the swamping problem with a mathematical example
patterned on Jenkin's, although not mentioning him by name.18And by the 1930s and
1940s, J. C. Willis was writing that 'Fleeming Jenkin... pointed out that unless a great
many individuals varied in the same direction over the whole of a considerable area, the
improvementwould promptly be lost by crossing.", By 1952, what had been a 'celebrated
difficulty' had grown into 'a most devastating criticism of many points of the Darwinian
theory ... Jenkin's criticism... probably did more to weaken Darwin's position than any
other single criticism'.20 Views such as these have led to today's narrow and prevailing
interpretation of Jenkin's work.
14 St-G. Mivart, On the Genesis of Species, 2nd edn, London and New York, 1871, 38.
15 M. Wagner, Die Darwin'sche Theorie und das Migrationgesetzder Organismen, Munich, 1868 (translated
by J. L. Laird as The Darwinian Theory and the Law of the Migration of Organisms, London, 1873).
16 G. J. Romanes, 'Physiological selection; an additional suggestion on the Origin of Species', The Journal of
the Linnean Society, Zoology Section (1886), 19, 337-51, see especially 339-40.
17 W. A. Herdman, 'Inaugural address on some recent contributions to the theory of evolution', Proceedings
of the Liverpool Biological Society (1889), 3, 5. Herdman also quotes the shipwreck story in full.
18 V. L. Kellogg, Darwinism To-Day, New York, 1907, 44-5.
19 Willis, op. cit. (3), 165; see also 5, 13-14, 25.
20 P. G. Fothergill, Historical Aspects of Organic Evolution, London, 1952, see especially 122, 132-3.
318
Susan W. Morris
We do not know when Darwin learned that Fleeming Jenkin was the author of the
article in the North British Review. While he had, when it was published, discussed the
review in depth with friends and colleagues (see below), 22 January 1869 is the first time
one sees Darwin link Jenkin's name to the critique when, in the context of describing
changes in the forthcoming (fifth) edition of the Origin, Darwin wrote to Wallace those
well-known words, 'I always thought individual differences more important than single
variations but now I have come to the conclusion that they are of paramount importance,
& in this I believe I agree with you. Fleming Jenkyn's [sic] arguments have convinced
me. '21
Wallace responded on 30 January, 'Dear Darwin, Will you tell me where are Fleming
Jenkyn's [sic] arguments on the importance of single variations. Because I at present hold
most strongly the contrary opinion, that it is the individual differences or general
variability of species that enables them to become modified and adapted to new
conditions.'22 Wallace's letter is striking in its urgency, and odd in that Wallace had not
only read Jenkin's article but had, only months before, published a lengthy response to it.23
Therefore, he must either have not yet known that it was Jenkin who had written the
North Britishessay, or he believed that Darwin referredto a new essay by Jenkin. Darwin,
apparently himself forgetting that Wallace was already familiar with Jenkin's review,
replied on 2 February,
I musthave expressedmyselfatrociously:I meantto say exactlythe reverseof what you have
understood.F. Jenkins[sic]arguedin N. Brit.R. againstsinglevariationseverbeingperpetuated
and has convincedme, thoughnot in quite so broada manneras hereput. I alwaysthought
individualdifferencesmoreimportant,but I was blindand thoughtthat singlevariationsmight
be preservedmuchoftenerthanI now see is possibleor probable.I mentionedthis in my former
note merelybecauseI believedthatyou had cometo a similarconclusion,andI like muchto be
in accord with you.24
What do these letters actually say? The cautionary, 'though not in quite so broad a
manner as here put' seems clearly intended by Darwin to deter Wallace from reading too
much into the preceding phrase that Jenkin has 'convinced' him. We should note the
intensity of Wallace's reply, as contrasted with Darwin's offhand approach, marked by his
somewhat careless use of language in the first letter. The whole subject of variations, he
implies by the word 'merely', is not crucial to him, he has raised the subject in the first
letter because he knows it to be of immediateinterest to Wallace, not necessarilyto himself.
The solicitous, 'I like much to be in accord with you' reinforces this point.
The problem of variations seems to have been of far greater import to Wallace than to
Darwin, an interpretationconsistent with the work of Bowler and Vorzimmer. Wallace's
views on variation were, at this time, still in ferment, whereas Darwin's views had been
21 BL (Add 46434). Fleeming is pronounced 'Flemming', hence Darwin's spelling. Jenkin was named after his
father's commanding officer, Admiral Fleeming.
22 DAR 106/7 (Ser. 2): 75-6.
23 Wallace's rejoinder to Jenkin (and to the Duke of Argyll) was included in Wallace's essay 'Creation by
law', QuarterlyJournal of Science (October 1867), 471-88; reprinted in Wallace's Contributions to the Theory
of Natural Selection, London, 1875, 264-301.
24 BL (Add 46434).
Fleeming Jenkin and The Origin of Species
319
settled for some time.25 Wallace's later reliance on neo- or ultra-Darwinism is further
evidence that individual differencesheld, for him, a far more incisive role in evolution than
they did for Darwin. Therefore, with respect to his above-noted correspondence with
Darwin, to distinguish their role from that of single variations was a coinpelling problem
for Wallace. This interpretation concurs with Vorzimmer's demonstration that Jenkin's
comments regarding variations were not significant to Darwin. Consequently, we might
infer that those comments cannot have been what led Darwin to say the essay had 'been
of more real use to me than any other'.
The other place in which Darwin connects Jenkin's review to the problem of variations
is in the Originitself. In the fifth and sixth editions (August 1869 and February 1872),
Darwin replaced what had been a paragraphon inheritancewith a discussion of variations
and individual differences, which reads, in part,
in a stateof natureof anyoccasionaldeviationof structure,such
I saw, also,thatthepreservation
as a monstrosity,would be a rareevent; and that, if preserved,it would generallybe lost by
subsequentintercrossingwith ordinaryindividuals.Nevertheless,until readingan able and
valuablearticlein the 'North BritishReview' (1867),I did not appreciatehow rarelysingle
could be perpetuated.26
variations,whetherslightor strongly-marked,
Historians usually stop the quotation at this point, raising the question of why, given
Vorzimmer's proofs of 1963, Darwin would have said that Jenkin's essay had brought to
his attention a point we now know he had been thinking about for twenty-five years. One
reading that the scholar may give to this curious passage, however, is that Darwin's
statement was simply gratuitous. There are other instances in the Origin where he falsely
credits other authors with the origin of his ideas. One is his citing the Saturday Review
(December 1859) for having convinced him to modify his calculations regarding the
denudation of the Weald when he had, in fact, at the prodding of Sir Charles Lyell and
others, already decided to change his Weald argument before the review appeared.27We
might infer, therefore, that Darwin used such citations as literary strategies to placate
critics, as much as to acknowledge genuine influences on his thinking.
A more revealing instance of such an attribution, however, is found in Darwin's
discussion of Mivart's criticisms. There, Darwin was again writing in general about ideas
he had developed long before, yet he states, 'I am bound to add, that some of the facts and
arguments here used by me, have been advanced for the same purpose in an able article
lately published in the " Medico-ChirurgicalReview ". '28 This citation is directly analogous
to the one concerningthe North British Review, in that Darwin used both to acknowledge
published sources for material he was borrowing. In the case of Jenkin's review, however,
25 P. J. Bowler, 'Alfred Russel Wallace's concepts of variation', Journal of the History of Medicine (1976), 31,
17-29.
26 Darwin, op. cit. (11), 178.
27 In the first two editions of the Origin, Darwin included his own projection of the time that had been
requiredfor the denudation of the Weald, an area in southeasternEngland.His 'crude notion' of 306662400 years
was immediately ridiculed, even by his friends, for the ineptness of the premisses he had used, and Darwin soon
regretted ever having included the discussion in his book. Several scholars discuss the changes Darwin made in
his Weald argument.Burchfielddiscusses the role of Lyell and Hooker, in particular.See Burchfield,op. cit. (5),
303-6; see also Darwin, On the Origin of Species, London, 1964, 286-87; Darwin, op. cit. (11), 483-4.
28 Darwin, op. cit. (11), 264.
320
Susan W. Morris
this becomes evident only if one reads beyond the point at which historians generally end
the quotation, for Darwin goes on to say,
I didnot appreciatehow rarely... variations... couldbe perpetuated.
The authortakesthe caseof
a pair of animals,whichproduceduringtheirlifetimetwo hundredoffspring,of which, from
variouscausesof destruction,only two on an averagesurviveto procreatetheirkind... He then
shows that if a singleindividualwere born...
and so on.29In other words, Darwin borrowed a mathematicalexample that appeared in
Jenkin's essay, and acknowledged his source with his customary display of generosity.
HENRY CHARLES FLEEMING JENKIN (1833-85), AND THE ORIGIN
OF AN ARGUMENT
Most of what we know of Jenkin has come from the Memoir of Fleeming Jenkin written
by his student and friend, Robert Louis Stevenson.30Although charming, this work often
presents Jenkin more as caricature than character. As one insightful friend later noted,
'Jenkin was not altogether fortunate in his biographer... Perhaps a narrative by a less
expert pen would have presented a larger figure.'31 Excessive reliance on the Memoir has
resulted in scholarly repetitions of the same anecdotes, occasionally supplemented with
information from obituaries on Jenkin, and to a limited extent with correspondence
preservedin the Kelvin collections at Glasgow and CambridgeUniversities.While drawing
on these standard resources, this paper also uses previously unexploited material to shed
new light on Jenkin's circle, and on how he became involved in the evolutionary debate.
Although generally described as Scottish, Jenkin was English on his father's side and
only partly Scottish on his mother's.32He was born and spent his early years at his father's
family home in Kent, about 40 miles from Darwin's Down. His father, Charles, was a naval
officer, and to the manner born. The family fortune having been lost, however, it was
always clear that Fleeming would have to make his own way in the world. Fleeming's
mother was an intelligent, flamboyant woman whose passions for music, literature and
politics dominated the small family's social relations. Whether living in Paris, Genoa,
Manchester or London, the Jenkins dwelt in political and literary circles.
Fleeming's formal schooling began in Scotland, where for three years his schoolmates
included Peter Guthrie Tait and James Clerk Maxwell. An only child, he then moved with
his parents to the Continent, living for various periods in Germany,Paris, and Italy, where
he matriculated at the University of Genoa, taking his MA with first class honours in 1850,
at the age of seventeen.
29 Darwin, op. cit. (11), 178.
30 Stevenson's Memoir of Fleeming Jenkin is the only full biography of Jenkin. It is included in Jenkin, PLS,
op. cit. (1), i, pp. xi-cliv, and was also published separately (New York, 1887) as well as in nine differenteditions
of Stevenson's collected works.
31 B. Matthews (ed.), 'Introduction' to Paperson Acting Vol. II: Mrs. Siddons as Lady Macbeth and as Queen
Katharine by H. C. Fleeming Jenkin, New York, 1915, on 16.
32 The Jenkin family had moved from York to Kent during the reign of Henry VIII,although Stevenson writes
that the family 'derived from Wales', thus some describe FleemingJenkin as Welsh. R. L. Stevenson, op. cit. (30)
(New York, 1887), 2.
Fleeming Jenkin and The Origin of Species
321
Already by this age, Jenkin had developed the appetite for melodramathat would inspire
a lifetime of varied interests and activities. Whether mounting the barricadesin the Paris
revolution of 1848, or dodging the crossfire in Genoa, whatever was theatrical and
dramatic was dear to him. His passion for the drama, especially, is an aspect of his life
warranting greater attention from scholars. Not content with reading plays, he also wrote
and staged them. He wrote drama criticism, papers on acting, and on Greek costume. His
favourite music, not surprisingly, was opera. His mature scientific work explored the
sound and articulation of the human voice. This latter work has been seen as the
outgrowth of his interest in electricalscience, which it certainly was, but we should not fail
to see it also as typical of his fascination with mechanisms of theatrical communication.
Jenkin was one of the first to grasp the significance of Edison's new phonograph as a
vehicle for permanentlypreservingrecords of the spoken word, particularlyfor preserving
the ephemeral 'actor's art'. Inevitably, this fascination with the tools of imaginative and
dramatic representation found its way into Jenkin's essays. The profession of engineering
itself served Jenkin's inventive and theatrical nature: building bridges, railroads, and
travelling round the globe on massive cable-laying expeditions were enterprises of
stagecraft, writ large. His world view looked out on a singular intersection of scientist and
artist, realist and romantic.33
Jenkin and his parents returned to England in 1851 when Fleeming entered upon an
engineering apprenticeshipwith the prestigious firm of William Fairbairnin Manchester.
This location brought him into contact with Joule's work on the mechanical equivalence
of heat, and with the newly developing ideas of thermodynamics. Following his
apprenticeship and a period in Switzerland working on railroads, he joined R. S. Newall
& Co., the firm then manufacturingthe first Atlantic telegraph cable. Although still quite
young, Jenkin apparently had charge of engineering and electrical work, machine design,
construction, and testing of cables and equipment.
In 1855, Jenkin began making frequent visits to the London home of Alfred and Eliza
Austin who would, in 1859, become his parents-in-law, and to whom he was introduced
by the Manchester novelist Elizabeth Gaskell. Alfred Austin and his two elder brothers,
John and Charles, were prominent members of Britain's legal establishment. They were
and had been close friends with Jeremy Bentham, James and John Stuart Mill, Carlyle,
Macaulay, and other luminariesof British literature, politics and economics.34A family of
brilliant and bold talkers, the Austins celebrated and debated the latest ideas in politics,
economics, science and the arts. It seems likely to have been in this company that Jenkin
first honed the skills in political economy that later enabled him to make seminal
contributions to economic science.35
33 Jenkin is a striking example of nineteenth-centuryinteractions between realism, romanticism, science and
art, as described by Brush, op. cit. (10), especially 482-93, and Brush, The Temperatureof History: Phases of
Science and Culture in the Nineteenth Century, New York, 1978.
34 J. S. Mill's Autobiography (Halifax, 1992, ed. A. 0. J. Cockshut) is replete with allusions to the Austins;
see, for example, ch. 3.
35 Jenkin is today more often cited in the economics literaturethan in the history of science. His contributions
were made in five papers, included in PLS,op. cit. (1), and republishedin 1931 by the London School of Economics
as No. 9 in Series of Scarce Tracts in Economic and Political Science.
322
Susan W. Morris
In the distinguished and argumentative society that gathered in the Austins' drawingroom, young Jenkin had opportunities to exercise his already broad range of intellectual
interests and to train his enthusiasm for verbal combat. Nearly every description of Jenkin
which has come down to us attests to his relentlesszeal for argument. Colvin describedhim
as 'too trenchant in reply and too pertinacious in discussion ... the most unflinching of
critics and disputants... He would eagerly watch for and pounce on your remarks, and the
futile or half-sincere among them he would toss aside with a prompt and wholesome
contempt, his eye twinkling the while. '36 And a son of Jenkin's, 'used not to understand
why Papa seemed so fond of contradicting everyone and of saying things exactly as he
meant them, especially to people we wished to make friends with'.3 Moreover, of his
essays in the North British Review, Jenkin himself confided to the editor, David Douglas,
that 'I hope for hearty abuse, which is much better than to be passed over in silence. I am
confident I can crack my opponents' heads if they will only fight.'38
By 1859, Fleeming Jenkin was evidently a young man on his way up. Through his cablework he became friends, and soon a business partner, with William Thomson, nine years
his senior and, at thirty-five, already an important figure in British science.39In 1861, the
British Association for the Advancement of Science formed a committee to determine and
fix standards for electrical measurements, appointing Jenkin to the post of secretary.
Collaborating with his old schoolmate, J. C. Maxwell, and with another Scot, Balfour
Stewart, Jenkin over the next few years experimented and wrote reports establishing the
units in which to express the magnitudes of various electrical phenomena.40By the early
1860s, then, Jenkin found himself in a circle comprising Thomson, Maxwell, Stewart and
their ilk, who shared a strong opposition to Darwin's theory. Thomson, in particular, was
exercised over the uniformitarian geological theory on which natural selection was
founded, and he profoundly influenced Jenkin's views.
Historians of science have tended to see Jenkin as a kind of Dr Watson to William
Thomson's Sherlock Holmes, a view seemingly encouraged by Thomson himself. That
Thomson regardedJenkin as his own creation would not seem to be in doubt: for example,
in his obituary of Jenkin, Thomson mentions himself five times in the first seven
paragraphs.None the less, the 'chilly tone of patronage' that marked Thomson's official
36 Sir S. Colvin, Memories and Notes of Persons & Places, 1852-1912, New York, 1921, 157-8.
37 CharlesFrewen Jenkin to R. L. Stevenson, 9 August 1887, Yale University, BeineckeLibrary,Robert Louis
Stevenson Collection (hereafterBeinecke Collection) no. 4982.
38 F. Jenkin to David Douglas, 2 March 1868, letter no. 114, 'Scrapbook', Douglas Papers, National Library
of Scotland (NLS). Having been introduced by P. G. Tait, Douglas wrote that Jenkin 'was soon to become one
of my most trusted allies'. (D. Douglas, 'Scrapbook', ch. 11, p. 143, Douglas Papers, NLS). Jenkin's letter was
occasioned by his NBR essay on trade unions ('Trade-Unions: How Far Legitimate', NBR (March 1868), 48 o.s.,
1-34); he and Douglas were considering republishingthe 'Trade-Unions' and the Origin of Species articles as a
book. See Jenkin to Douglas, 12 February 1868, letter no. 113, Douglas 'Scrapbook', NLS. I am most grateful
to Joanne Shattock for personal communication and material about Douglas and the North British Review.
39 Sir William Thomson was not created Lord Kelvin until 1892, well beyond the time period treated in this
paper. To maintain consistency with the quotations in the paper, I refer to him throughout as Thomson, rather
than Kelvin.
40 The articles appearedindividually in the annual Report of the BritishAssociation for the years 1862-64 and
1867. They were collected and reprinted in Fleeming Jenkin (ed.), Reports of the Committee on Electrical
Standards, London and New York, 1873.
Fleeming Jenkin and The Origin of Species
323
recollections of Jenkin was startling even to the latter's family and friends. However, in the
early years of their friendship Jenkin certainlywas a devoted acolyte of the dynamic genius
whom Jenkin's wife dubbed 'Professor Apollo'.41
One of Thomson's earliest and lifelong interests concerned the physics of the earth and
the solar system. He took as his starting point Fourier'swork on heat conduction, and he
immediately applied to the earth the implications of the new researchesin thermodynamics
in the 1850s.4"Thomson held that the sun was a fluid mass, gradually cooling, and that the
continuation or maintenance of its heat came from gravitational contraction. This was
consistent with his view that gravity was 'the original form of all the energy in the
universe."'4The sun's heat, in other words, was the result of mechanical action.
In the early 1850s, Thomson succeeded in reconciling the apparently paradoxical
conclusions from the researchesof Sadi Carnot and James Joule that when work was done,
heat (energy) was both lost and conserved. Thomson showed that although heat (energy)
was not lost absolutely, it was, largely through friction, 'dissipated', or rendered
unavailable to do useful work, as the bodies doing the work approached a uniform
temperature.This implied that although the total amount of energy in the universe would
remain forever constant, its ability to do work would gradually but continually diminish.
This did not ipso facto imply a state where everything would be cold:
Whenall the chemicalandgravitationenergiesof the universehavetakentheirfinalkineticform,
the result will be an arrangementof matterpossessingno realizablepotential energy,but
mixtureof all that is now definiteand separate.44
uniformlyhot - an undistinguishable
Meanwhile, beginning in the 1830s, debate flourished between those geologists known
as uniformitarians and those called catastrophists.45'Uniformitarianism', as William
41 In addition to the obituary, Thomson composed a 'Note by Sir William Thomson on Fleeming Jenkin's
contributions to electrical and engineering science', included in the posthumous publication of Jenkin's papers
and biography (PLS,op. cit. (1)). Sidney Colvin to R. L. Stevenson, 13 September[1887]: '[Mrs Jenkin and I have]
settled a few remaining points as to the memoir, & chiefly, to cut out altogether the two concluding paragraphs
of Sir W. Thompson's [sic] note. Left standing, their chilly tone of patronage could not but shock: without them,
& headed as we have now headed it, 'Note by Sir W.T. on F.J.'s contributions to Electrical and Engineering
Science', the thing will read all right and in its place. Mrs Jenkin, when the book comes out, will write to Sir W.T.,
throwing the responsibility of the deletion on me as editor, and saying that as his (F.J.'s) general intellectual
powers & pursuits have been so fully dwelt on in the memoir, it seemed that the reference to them here might
be spared.' Beinecke Collection, no. 4390. Thomson's obituary on Jenkin is found in 'Obituary notices of fellows
deceased', Proceedingsof the Royal Society of London (1885),39, pp. i-iii and was reprintedin Thomson's (Baron
Kelvin's) Mathematical and Physical Papers, 6 vols., Cambridge, 1911, vi, 335-8.
42 Smith and Wise, op. cit. (13). Part III of this work, 'The economy of nature: the great storehouse of
creation', contains extensive discussion and explanation of Thomson's work in thermodynamics and its
application to the questions of the ages of the sun and earth. See especially chs. 15, 16 and 17, pp. 524-611.
43 W. Thomson and P. G. Tait, 'Energy', Good Words (1862), 3, 601-7, on 606.
44 Thomson and Tait, op. cit. (43), 606.
45 The standard work on this subject remains W. F. Cannon 'The uniformitarian-catastrophistdebate', Isis
(1960), 51, 38-55. Also useful for understandingthe various schools existing in nineteenth-centuryBritishgeology
is C. Smith, 'Geologists and mathematicians: the rise of physical geology', in Wranglersand Physicists: Studies
on Cambridge Physics in the Nineteenth Century (ed. P. M. Harman), Manchester, 1985, 49-83. M. J. S.
Rudwick points out that 'the debate [between uniformitariansand catastrophists]... was never sharply polarized
into factions or parties'. See his 'Introduction' to C. Lyell, Principles of Geology, facsimile of first edition (ed.
M. J. S. Rudwick), Chicago and London, 1990, especially p. liv.
324
Susan W. Morris
Whewell famously defined it, meant that geological activity or causes had been uniform,
in kind and in degree, throughout time. It denied that geological agents, such as volcanoes,
earthquakes, or erosion, had been any more extreme or rapid in the past than in the
present, or that any agents had existed in the past which did not obtain in the present. In
keeping with these views, uniformitarians and catastrophists tended to divide over the
extent to which the world was 'progressive'. In practical terms this meant evaluating
whether the earth (or any other body in the solar system) had originatedin a primitive state
and was constantly evolving toward an eventual end state quite differentfrom its original.
Charles Lyell, the leading advocate of uniformitarianism, denied this was possible and
believed instead in a 'ceaseless repetition of continent-raising and continent-ending'
processes.46
Obviously, the notion of non-progression held by Lyell was incompatible with the new
thermodynamic principles enunciated by Thomson. If all natural processes generated
friction and consequently heat, which was thereby dissipated so that it was no longer
available to do further work, then the sun and the earth and the entire solar system had
finite lives.
While not yet exercised over (or perhaps aware of) the large bank of time being drawn
on by the uniformitarians,Thomson in the 1850s began arguing that the idea of a cyclical
and non-progressive universe with 'no vestige of a beginning, no prospect of an end'47
contravened the physical idea (which we now recognize as fact) of the dissipation of
energy. Yet even Thomson was, at the time, given to using terms such as 'countless ages'
and 'endless futurity' while writing, with no apparentirony, that 'it seems not improbable
that the earth has been efficiently illuminated by the sun alone for not many times more
or less than 32,000 years' and, 'I conclude that sunlight cannot last as at present for 300,000
years. 48 Hardly an 'endless futurity'. And even while employing such rhetoric as
' countless ages', Thomson would write that 'the end of this world as a habitation for man,
or for any living creature or plant at present existing in it, is mechanically inevitable;
and ... purely mechanical reasoning shows a time when the earth must have been
tenantless'.49
46 Cannon, op. cit. (45), 38. Ironically, considering its importance to Darwin, Lyell's uniformitarianismwas
essentially opposed to organic evolution. Indeed Lyell, in the 1830s-40s, denied the possibility of 'the successive
development of animal and vegetable life, and their progressiveadvancementto a more perfect state', and by 1850
had modified his views only far enough to say that 'the popular theory of the successivedevelopment of the animal
and vegetable world ... rests on a very insecure foundation'. Principles of Geology, 2nd edn, 3 vols., London,
1832-33, ii, 157; 1850 quote from 8th edn, London, 144. The extent to which Darwin adopted Lyell's
uniformitarian theory is analysed in R. Hooykaas, The Principle of Uniformity in Geology, Biology and
Theology, Leiden, 1963, and in M. Bartholomew, 'The non-progressof non-progression:two responses to Lyell's
doctrine', BJHS (1976), 9, 166-74. Added irony, given William Thomson's opposition to Darwinism, is that
Thomson's work, to a large extent, helped 'lay the ground for a modern, evolutionary view of the earth' and thus
made Darwinian evolution more plausible. See R. H. Dott, Jr, 'James Hutton and the concept of a dynamic
earth', Toward a History of Geology (ed. C. J. Schneer), Cambridge, Mass. and London, 1969, 122-41, on 140.
47 The phrase, of course, is from the 'founder of modern geology', James Hutton (1726-97), in Theory of the
Earth, 2 vols., Edinburgh, 1795, i, 200.
48 W. Thomson, 'On mechanical antecedents of motion, heat, and light', Report of the British Association
1854, Section Transactions, 59-63, on 61; 'On the mechanical energies of the solar system', Philosophical
Magazine, Ser. 4 (1854), 8, 409-30, on 429.
49 Thomson, 'Mechanical antecedents', op. cit. (48), 61.
Fleeming Jenkin and The Origin of Species
325
Thomson's projections about the ultimate age of the sun were based on the sun's
estimated mass, and the known rate at which it 'gave away' its energy. For the earth,
Thomson based his calculations on its temperaturegradient, on the assumption that the
earth in its primitive state had been uniformly molten and was gradually cooling in accord
with Fourier's heat equations, and on the known melting points of rock. Importantly, he
calculated that no chemical reactions in the interior of the earth could possibly account for
the amount of heat actually contained in it. A corollary was that the continual cooling of
both the earth and the sun, caused by the dissipation of energy, meant that geological
processes could not possibly have remained constant, or uniform, over the immense
periods of time envisioned by the Lyellians.
That Thomson was eager to press this idea on geologists may be surmised by the
conclusion to his 1852 paper 'On a universal tendency in nature to the dissipation of
mechanical energy':
Withina finiteperiodof timepast the earthmusthavebeen,and withina finiteperiodof time
to comethe earthmustagainbe, unfitfor the habitationof manas at presentconstituted,unless
operations have been, or are to be performed, which are impossible under the laws to which the
known operations going on at present in the material world are subject.50
Over the next several years Thomson would, with more felicitous phrasing, reiterate this
view time and again.
For example, in two papers, 'Physical considerations regarding the possible age of the
sun's heat' and ' An examination of some points in the doctrine of the internal heat of the
Globe', delivered at the British Association meeting in Manchester in 1861, Thomson
launched what was to become an implacable attack against uniformitarianism. Jenkin,
apparently at Thomson's request, helped to see Thomson's papers onto the meeting's
agenda. Since a broken leg prevented Thomson's attendance, Jenkin wrote to him from
Manchester that,
after some writing and enquiry I found Prof. Rogers had taken charge of your papers, so I did not
think you would like me to interferefurther: but today the Sun paper was on the list but not read
and stands first for tomorrow. I am afraid the Earth will not come on or will come on far too late.
The geologists seem to have referredit to Section A and by that time Section A was very full. I
am very sorry for this as I think it would have cut some of their arguments short ... I am sorry I
could not do more for your papers, I wish I had had them from the first.
A few days later Jenkin wrote again,
to give you some private news of the British Association. I am sorry to say the paper on the Sun
being put off to Wednesday had no justice done to it: being cut short by Airey [sic] and not
discussed - the paper on the Earth met with a somewhat better fate and was followed by a good
discussion: but I wish you had been present.51
We can only speculate whether the discussion might have changed had Thomson indeed
been present. Curiously, the official Report of that BAAS meeting makes no mention of this
50 Thomson, 'On a universal tendency in nature to the dissipation of mechanical energy', Philosophical
Magazine, Ser. 4 (1852), 4, 304-6, on 306.
51 Both letters are undated, but from the contents we can deduce that the first letter was written on Tuesday
10 September1861. Both are in CambridgeUniversity Library,Kelvin Manuscript Collection: the first is no. J37,
Add 7342; the second, no. J36, Add 7342.
326
Susan W. Morris
paper on the earth, and the only printed records of it appear to have been in The London
Review and The Athenaeum.52
Some have suggested that Thomson's BAASpapers of 1861 may have been provoked by
his reading of Darwin's Origin.53 Burchfield, for example, posits that until Thomson
learned of Darwin's calculation of some 300000000 years for the denudation of the Weald,
he may not have realized what immense periods of time were actually envisioned by the
uniformitarianswhen they spoke of 'countless ages' and of 'times incalculably remote'.
Certainly at ManchesterThomson aimed directly at Darwin when asking, 'what are we to
think of such geological estimates as 300,000,000 years for the "denudation of the
Weald" ?' Yet Thomson's argument still appears to have been aimed against uniformitarianism. His paper on the sun, for example, ended with the statement that, 'it seems
therefore, on the whole, most probable that the sun has not illuminated the earth for
100,000,000 years, and almost certain that he has not done so for 500,000,000 years'. He
then reassertedhis 1852 conclusion, but now expressed with uncharacteristiceloquence:
As for the future,we maysay with equalcertaintythat inhabitantsof the earthcannotcontinue
to enjoy the light and heat essential to their life for many million years longer, unless new sources,
now unknown to us, are prepared in the great storehouse of Creation.54
Following the BAAS meeting, Thomson published a flurry of articles in the lay press:
first, an abstract of the 'Age of the sun's heat' in The Athenaeum; next, the full paper in
Macmillan's; finally an article on 'Energy', co-written with P. G. Tait, in the Presbyterian
journal Good Words.55 These actions readily convey the importance to Thomson of
bringing the principles of this new science - the conservation and the dissipation of energy
- and their implications for the earth and the sun, to the attention of a wide general
audience. Certainly the time was right to 'raise the post-Darwinian debate above the level
of popular controversy', as Smith and Wise suggest,56 and place it in the context of the new
thermodynamics. Still, beyond the comments he had already voiced, Thomson made no
further attacks on natural selection per se, concentrating his attention instead on the
geophysics that was his forte.
Thomson delivered a revised and retitled version of his BAAS paper on the earth in April
1862 in Edinburgh, and saw it published in January 1863.57 In this technical article,
52 The London Review, 14 September 1861, 348, and The Athenaeum, 28 September 1861, 414, both record
the paper on the earth as having been read to Section C, Geology, on Wednesday 11 September 1861. Given
Jenkin's comment, we might infer that since Section A (Mathematical and Physical Science) was full, the paper
was referredback to Geology. The Times (Thursday 12 September 1861, 7), Smith and Wise, op. cit. (13), and
Burchfield,Kelvin, op. cit. (13), mention only the paper on the 'Age of the sun's heat' in connection with the 1861
BAAS meeting.
53 See, for example, Smith and Wise, op. cit. (13), 524. Both Burchfield,Kelvin, op. cit. (13), and Smith and
Wise, op. cit. (13), especially 497-648, contain thorough discussions of Thomson's participation in this debate,
including the philosophical and theological beliefs that stirred Thomson's technical work.
54 W. Thomson, 'Physical considerations regardingthe possible age of the sun's heat', Report of the British
Association 1861, Section Transactions, 27-8, on 28.
55 Anon, "'Physical considerations regardingthe possible age of the sun's heat" by Professor W. Thomson',
The Athenaeum,28 September1861, 412-13. W. Thomson, 'On the age of the sun's heat', Macmillan's Magazine
(March 1862), 5, 388-93. Thomson and Tait, op. cit. (43).
56 Smith and Wise, op. cit. (13), 528.
57 W. Thomson, 'On the secular cooling of the earth', read to the Royal Society of Edinburgh,28 April 1862,
published in the Phil. Mag., Ser. 4 (1863), 25, 1-14.
Fleeming Jenkin and The Origin of Species
327
combining recent data on temperature gradients with Fourier's equations for heat
conduction, Thomson conjecturedthat the age of the earth ranged between 20 million and
400 million years, with the most likely figure around 98000000 years. Then in 1865, in the
absence of any visible concessions by the uniformitarians in the intervening years,
Thomson continued his attacks on Lyell's geology with the haughty "'Doctrine of
Uniformity" in geology briefly refuted'.58 In May 1866, he delivered Cambridge
University's Rede Lecture, speaking on 'The Dissipation of Energy', wherein he presented
new ideas on the age of earth, and where he repeated verbatim the concluding lines of his
1852 paper (above).59
It seems probable that readers such as Darwin saw Thomson's papers as a continuation
of the uniformitarian-catastrophist debate in which Thomson's former Cambridge
mathematics coach, William Hopkins, a respectedgeologist, was prominent in leading the
anti-uniformitarianforces. The difference between an argument based on primitive heat
and one based on the dissipation of energy was subtle, and while Hopkins himself had
attempted to awaken his fellow geologists to the importance of thermodynamicsfor their
field, it cannot have been obvious to non-physicists how Thomson was adding anything
new to the debate, beyond abstruse mathematics and a shrill tone.60
Not surprisingly, therefore, Darwin's reaction to Thomson's polemics was one of
indifference. Indeed, he was almost contemptuous of the arguments levelled at him from
physics and astronomy. In 1866, for example, he snapped at J. D. Hooker, 'I cannot think
how you can attach so much weight to the physicists, seeing how Hopkins, Hennessey,
Haughton, and Thomson have enormously disagreed.'61
Darwin's pique was justified. We have already seen that Thomson's own estimates for
the age of the sun had varied between 32000 years (in 1854) and 500000000 years (in 1861).
This was in part due to changes in Thomson's ideas on the origin of the sun's heat.
Additionally, the available data were constantly changing, particularly in new areas of
research such as the temperature gradients of earth, so that while Thomson's methods
remained consistent, the solutions to his equations varied as a result of changing their
initial conditions. Moreover, differencesin their opinions on the rigidity of the earth and
the thickness of its crust divided the conclusions of Thomson from those of Hopkins. For
his part, Samuel Haughton changed from an estimate (in 1862) of 100 million years to (in
1864) 2300 million.62
None the less, Darwin's complacency was to be short-lived. It was impossible to
accommodate both uniformitarianismand natural selection within the new principles of
58 W. Thomson, 'The "Doctrine of Uniformity" in geology briefly refuted', read to the Royal Society of
Edinburgh, 18 December 1865, published in the RSE Proceedings (1866), 5, 512-13.
59 The Rede Lecture was not published but an extensive account of it appeared in the Cambridge Chronicle,
26 May 1866, and that account was reprintedin S. P. Thompson, The Life of Lord Kelvin, 2 vols., 2nd edn, New
York, 1976, i, 437-42.
60 Hopkins's BAAS Presidential Address presents an example of his views regarding the application of
thermodynamics to geology; see 'Address by William Hopkins, Esq.', Report of the British Association 1853,
pp. xli-lvii.
61 Darwin to J. D. Hooker, 28 February 1866, DAR 94: 31-2. Actually, only one of this group, Thomson,
would have been considered a physicist. William Hopkins, while well known as a mathematician,was principally
regarded as a geologist, as was the Rev. Samuel Haughton.
62 For a discussion of Haughton's views, see Burchfield,Kelvin, op. cit. (13), 100-3.
328
Susan W. Morris
thermodynamics. Consequently, after the uniformitarian-catastrophistarguments of the
1830s-50s, and the development of thermodynamicsin the 1850s, the 1860s were primed
for a clash between major new scientific concepts. Rival theories faced an arduous struggle
for existence in the scientific world and in the world of public opinion.
If we can paraphrase Carlyle's observation that the printing press was the only pulpit,63
then we might say that the age-of-the-earthsermons thundering from the pen of William
Thomson, relying on technical language and appearing largely in scientific journals, had
little prospect of influencing a lay audience. Jenkin's essay, in contrast, would bring the
physical arguments against Darwinism directly to a public that had been largely ignorant
of them, posing a vigorous new threat to the authority that natural selection was just
beginning to wield in the congregation of national opinion. The thrust of Jenkin's article
would be to show the public that there were strong mathematical and scientific, as
compared with religious, grounds on which to oppose natural selection. For his readers,
his review would remove the Origin controversy from the domain of religion, and arm
them to debate in the domain of science.
Arming their readers to debate was an important feature of the quarterly reviews. As
scholars, we tend to look back on the evolution controversy as a clash between Darwinians
and anti-Darwinians, neglecting to recognize the presence of an important third party: the
articulate classes' then arising in every walk of British society.64Education was a new
consumer-good for a growing middle class. Displaying one's knowledge of current issues
was a mark of status and cultivation, as well as a means of advancing in this socially
competitive world. With Britain's inadequate formal schooling system, however, the
'educated and would-be-educated' depended on books and the serious periodicals for the
knowledge they craved.65Contributors to these periodicals were 'entrusted with nothing
less than the "momentous task of forming national opinion". 166 Despite Darwin's
occasional claims of indifferenceto public support, the Origin was written in a style clearly
designed to appeal to, and persuade, that audience. Both Darwinians and their critics, by
publishing their evolutionary debate in the periodical press, aggressively sought to tip the
scales of public opinion in their favour.67
Given what we know of him, Jenkin probably relished the controversy. Certainlyit does
not strain credibility to imagine that in his 1860s milieu of anti-Darwinian electricalstandards men, their casual conversation turned occasionally to Darwin and natural
selection.
JENKIN'S REVIEW:'THE
ORIGIN OF SPECIES'
The existing evidence suggests that Jenkin first drafted his essay in 1862 or before, not in
1867 as has been generally assumed. In the early 1860s, his interest in evolution had been
aroused by a number of events. Through his cable-laying voyages beginning in the 1850s,
63 From W. E. Houghton, 'Periodical literatureand the articulate classes', in The Victorian Periodical Press:
Samplings and Soundings (ed. J. Shattock and M. Wolff), Toronto and Leicester, 1982, 3-27, on 9.
64 Houghton, op. cit. (63), 7.
65 Houghton, op. cit. (63), 4.
66 Houghton, op. cit. (63), 7, quoting J. Morley in the Fortnightly Review, n.s. (1867), ii, 292.
67 Lyell's Principles was similarly aimed at a lay audience. See M. Rudwick, op. cit. (45), pp. xi-xii.
Fleeming Jenkin and The Origin of Species
329
Jenkin had become intrigued with the tiny and mysterious creatures he found clinging to
cables retrieved from the sea floor.68 Then in 1861, he had become involved with
Thomson's BAAS papers. Moreover, on the BAAS electrical-standardscommittee, he was
surroundedby a circle of anti-Darwinian physicists. Thus it seems not unlikely that in this
environment Jenkin attempted his own critique, aimed at Darwin specifically, rather than
at uniformitarianism.
Evidence does exist for this conclusion, such as the clear statement from Stevenson that
'in the year 1863... [Jenkinand his wife] moved into a cottage at Claygate near Esher... He
had begun by this time to write. His paper on Darwin ... had indeed been written before
this in London lodgings.'69
Further corroboration for an early dating of the essay comes from its text, for it draws
on ideas developed by William Thomson prior to 1863, but not at all on arguments and
calculations made by Thomson in 1863-67. Moreover, it is certain that Jenkin reviewed
either the first or the second edition of the Origin, notwithstanding the apparent
assumptions to the contrary by historians. In the fourteenth paragraph of Jenkin's essay,
he quotes Darwin, giving the location of the quoted sentence as 'p. 153' of the Origin, a
location it enjoyed in the first two editions only. This perhapsjustifies, or at least explains,
Jenkin's discussion of Darwin's Wealden calculation, which appeared only in the Origin's
first two (November 1859 and December 1859) printings.70
It seems unlikely, however, that Jenkin showed his draft to any of his scientific
colleagues, for surely such keen mathematicians as Thomson or, especially, Maxwell
would have noticed a significant error in the mathematics of Jenkin's 'swamping'
argument. More probable is that Jenkin discussed the draft with his father-in-law, Alfred
Austin, whom Jenkin regarded as 'the cleverest man in London', and this probably
accounts for the essay's reading like a legal brief.7' Surely the theatrics of the courtroom
would have appealed to Jenkin's tastes.
Lawyers distinguish between cases based on facts and those based in law. In his essay,
Jenkin quickly establishes that his case against natural selection will be based in law. He
first summarizes Darwin's theory, then notes that it bases 'large conclusions' on 'small
facts'. Only such specialists as Darwin can judge the facts, 'but the super-structurebased
68 Anne Jenkin to Robert Louis Stevenson, 28 December [1885?], Beinecke Collection, no. 4978.
69 Stevenson, Memoir, PLS, op. cit. (1), i, pp. lxvii-lxviii. In writing the Memoir, Jenkin's widow provided
Stevenson with access to 'two huge portmanteaux of family letters & papers', Jenkin's notebooks, and other
materials (see Anne Jenkin to Stevenson, n.d. and 2 September[1886?], Beinecke Collection, nos. 4977 and 4979).
Moreover, while Anne Jenkin did not actually collaborate with Stevenson in composing the Memoir, as was
originally contemplated (see Henry James to Stevenson, 8 December [1885], Beinecke Collection, no. 4926), she
did review each chapter as it was completed, writing extensive comments and corrections in the margins, and in
places directing Stevenson to consult specific documents. She also reviewed the final proofs before they were
printed. Thus it seems unlikely that an error could have been made in something as important to Jenkin, and as
easily verified, as the date when he first wrote his Darwin essay.
70 For example, Burchfield: 'Jenkin had before him the fourth edition of the Origin, from which all reference
to the Weald had been removed.' op. cit. (5), 307. Vorzimmer: 'Jenkin's review... was based essentially on the
fourth edition which had appeared the previous December', in 'Blending' op. cit. (5), 386; and 'It was the
appearanceof the fourth Origin ... that served as the object of FleemingJenkin's review in the NBR the following
spring. The delay between the publication of the Origin and the appearanceof the review was a sign of the pains
taken by the author to gather all his critical evidence', Controversy op. cit. (5), 148.
71 Jenkin to David Douglas, 10 February 1868, letter no. 112, Douglas Scrapbook, NLS.
330
Susan W. Morris
on those facts enters the region of pure reason, and may be discussed apart from all doubt
as to the fundamental facts'.72
This strategy gave Jenkin two advantages: (1) he could concede the facts and yet yield
nothing to his opponent and, (2) he could appeal to scientific law, in which the case for
physics - the science of Newton - would appear far stronger than that for geology or for
evolution. By invoking this strategy, Jenkin implicitly contrasted his approachwith that of
Darwin, who built his theory upon the accretion of just those facts that Jenkin dismissed.
In thus basing his case on (physical) law, Jenkin seized the philosophical high-ground,
where physics reigned, and he undoubtedly hoped no one would notice that the actual
'law' on which he relied (now enshrined as the Second Law of Thermodynamics)was, at
the time, little better grounded than Darwin's.
He then raised five questions, in the same order in which he summarizedthe theory: (1)
'Can natural selection choose special qualities, and so breed special varietiesas man does?'
- meaning, is natural selection analogous to artificial selection? (2) Is the power to
'magnify the peculiarities [distinguishing] breeds from their original stock' unlimited? can it, in other words, create new species? Next, having already alluded to the assurances
of geologists that 'the habitable world has existed for countless ages', a lawyer-like Jenkin
asked, (3) 'Is there no other evidence than that of geology as to the age of the habitable
earth? - and what is the value of the geological evidence?' He then inquired, (4) whether
'mere difficulty in classifying organized beings' mandates our expecting 'that they have
had a common ancestor?' Finally, he asked, (5) what value are we to attach to 'minor facts
supposed to corroborate the new theory?'
These questions were not new with Jenkin. The first and last, in particular, had been
treated by numerous critics, but Jenkin must have felt he had something new to add.
Notably, he asserts that thus far Darwin's critics 'have been chiefly men having special
knowledge similar to [Darwin's] own', thus ignoring the many religious arguments that
had been levelled at natural selection, and laying the ground for a critique based entirely
in science. Jenkin's approach thereby reflects 'the detachment and independence"'7of his
own religious views and, in this sense, the North British Review was an ideal location for
the article, being a journal intent on asserting its independence from religious influence.
Having introduced his themes, Jenkin immediately mixed up his first two questions. His
confusion might have arisen, in part, from his using this essay as an initial foray into a
subject - population dynamics - that he would explore in detail in two later North British
Review articles.75 Jenkin consequently began his review by answering his second question
- whether the range of variabilityis infinite - arguing for an asymptotic limit to the extent
of any variability.
In opening with a question on limits, Jenkin was asking of natural selection essentially
the same question as that which Sadi Carnot had asked of heat engines. In 'Reflexions on
72 Jenkin NBR, op. cit. (1), 278.
73 Jenkin, NBR, op. cit. (1), 278-9.
74 Quote from Graham Balfour, The Life of Robert Louis Stevenson, 2 vols., New York, 1901, i, 113.
75 Anon. [F. Jenkin], 'Fecundity, fertility and sterility', December 1867, and 'Trade-unions: how far
legitimate', March 1868. Population was also a concern of Jenkin's father-in-law, Alfred Austin, who had been
a Poor Law Inspector.
Fleeming Jenlzin and The Origin of Species
331
the motive power of fire', a paper with which Jenkin was undoubtedly familiar,
considering its importance for the thermodynamics of William Thomson, Carnot had
inquired, 'can we set a limit to the improvement of the heat engine, a limit which, by the
very nature of things, cannot in any way be surpassed?Or, conversely, is it possible for the
process of improvementto go on indefinitely?'76 Clearly, Jenkin believed that, at least with
respect to natural selection, it could not:
Hundredsof skilfulmen are yearlybreedingthousandsof racers.Wealthand honourawaitthe
manwho canbreedone horseto runone partin fivethousandfasterthanhis fellows.As a matter
of experience,haveourracersimprovedin speedby one partin a thousandduringthe lasttwenty
?... We arethusled to believethat whatevernew pointin the variablebeast,bird,or
generations
flower,be chosenas desirableby a fancier,thispointcan be rapidlyapproachedat first,but that
the rateof approachquicklydiminishes,tendingto a limit neverto be attained.77
He then introduced his metaphor of the sphere of variation, an argument,essentially, for
the stability of species. This was the point used so extensively by Mivart7"and which, postVorzimmer, has received the greatest attention from historians:
A givenanimalor plant appearsto be contained,as it were,withina sphereof variation;one
individuallies near one portionof the surface,anotherindividual,of the same species,near
anotherpart of the surface;the averageanimalat the centre.Any individualmay produce
descendantsvaryingin anydirection,but is morelikelyto producedescendantsvaryingtowards
the centreof the sphere,and the variationsin that directionwill be greaterin amountthan the
variationstowardsthe surface.79
Turning to his first question, on the creation of new species, Jenkin then made the
'swamping' argument that came to wield so much influence. As others did, he criticized
Darwin's theory on the grounds that it accounted for the adaptation, but not the creation,
of characteristics: 'such a process of improvement as is described [by natural selection]
could certainly never give organs of sight, smell, or hearing to organisms which had never
possessed themI.80
Continuing with the argument, Jenkin noted a distinction between what he called
'common variations' (Darwin's individual differences) and saltations, or sports. He
developed an ingenious mathematical argument, deducing that, with respect to sports, the
mathematical probabilities were more than fifty to one against the survival and
reproductionof any given saltation. Yet Jenkin had carelesslymade an error.Where he had
76 S. Carnot, Reflexions On the Motive Power of Fire: A Critical Edition with the Surviving Scientific
Manuscripts (tr. and ed. Robert Fox), Manchester, 1986, 63.
77 Jenkin, NBR, op. cit. (1), 281-82. We do not know whether Jenkin, at this point, may also have had in mind
the economic notion of diminishing returns. His economics writings are remarkably free of biological and
evolutionary metaphors.
78 Mivart, op. cit. (14); see especially ch. 5.
79 Jenkin, NBR, op. cit. (1), 282. For all the attention it has received, no one has pointed out an apparent
fallacy in this argument: Jenkin's 'limit in a given direction' applies to change in one trait only, not to the whole
organism, whereas evolution implies changes in a number of traits, each of which, varying in a given direction,
could actually have a limit. Using Jenkin's notion of the sphere of variation, it would seem to be specific traits
that lie within the spheres, not whole beings, as he imagined.
80 Jenkin, NBR, op. cit. (1), 288.
332
Susan W. Morris
written, '[of one million born] ... the chances are fifty to one against the gifted individuals
being one of the hundred survivors', he had meant to write 'one of the ten-thousand
survivors', a slip embarrassinglymade public in letters to Nature in 1871.81 That modern
scholars seem not to have noticed the error suggests they have not read this section of
Jenkin's essay as carefully as they might have. Still, readers then and now may have
overlooked th& slip because, in appealing to a general audience, Jenkin immediately
converted the abstruse mathematics into a striking melodrama of a hypothetical 'white
man ... wrecked on an island inhabited by negroes'.82
It seems possible that Jenkin was inspired to this frequently-quotedfable by the actual
shipwreck of the P&O steamer Alma in the Red Sea in 1859, an incident involving several
of Jenkin's cable-laying colleagues, and in which his employer, R. S. Newall, played the
genuine role of hero.83Alternatively, the scenario may have come from Jenkin's mother
who, by the early 1860s, was herself a successful author of Gothic romances, and who had
been raised in the West Indies. In Jenkin's story, his 'shipwrecked hero' gains every
advantage conceivable in the struggle for life. He becomes king, kills many blacks (negative
selection), has many children (positive selection), but Jenkin asserts that countless
generations 'would not suffice ... to turn his descendants white'84 because the hero's traits
would be increasingly blended in his descendants. Jenkin asks whether the population
would gradually acquire the 'energy, courage, ingenuity, patience, self-control, endurance'
of the hero, 'those qualities, in fact, which the struggle for existence would select, if it could
select anything ? 85
In his ambiguous style of writing, Darwin had sometimes implied that small saltations
would actually be reproduced throughout a population if that population was small and
isolated, but Jenkin, by having his island scenario stand for just such an isolated
population, effectively discredited that notion. Having thus dispensed with sports, Jenkin
then turned to evolution via individual differences. Again arguing from mathematical
probabilities, he showed that even a common variation would be diluted into oblivion,
unless it appearedsimultaneouslyin at least half the membersof a population. Evoking his
earlier shipwreck story, he concluded with the oft-quoted,
If it is impossible that any sport or accidental variation in a single individual, however favourable
to life, should be preserved and transmitted by natural selection, still less can slight and
imperceptible variations, occurring in single individuals, be garnered up and transmitted to
continually increasing numbers; for if a very highly favoured white cannot blanch a nation of
81 : 'Studens', 'The genesis of species', Nature, 2 March 1871, 347; The Author of the Article [F. Jenkin], 'The
origin of species', ibid., 30 November 1871; A. S. Davis, 'The North British Review and the origin of species',
ibid., 28 December 1871, 161. The corrections in Jenkin's anonymous reply were unfortunatelynot appended to
the essay when it was republishedin 1887, leaving readersto puzzle over the calculations, as Darwin perhaps had
done.
82 Jenkin, NBR, op. cit. (1), 289-90.
83 Werner Siemens, making the passage with Newall, includes a fascinating account of the shipwreck in his
Inventor and Entrepreneur:Recollections of Werner von Siemens, 2nd English edn, London and Munich, 1966,
138-44. A long article also appearedin the Times: 'The loss of the Alma', The Times, 7 July 1859,5. I thank Bruce
Hunt for bringing this incident to my attention.
84 Jenkin, NBR, op. cit. (1), 289-90.
85 Jenkin, NBR, op. cit. (1), 290.
Fleeming Jenlzin and The Origin of Species
333
negroes,it will hardlybe contendedthata comparatively
verydull mulattohas a good chanceof
producinga tawnytribe.86
At this point historians, believing they have now read Jenkin's important criticism, often
seem to quit the essay. However, Jenkin's careless order in answering his first two
questions, and his failure to detect his mathematical error, suggest he did not labour
overlong on these two sections, and this would imply, in turn, that in his mind they were
not the heart of his argument. Indeed, at this point Jenkin had just brought his locomotive
up to speed. Scholars therefore abandon the essay at just the point where a discussion of
Darwin's most formidable obstacle begins, for in the ensuing section, titled 'Lapse of time',
Jenkin investigated whether the earth was sufficiently old to have allowed natural selection
to work, predictably seeking his answers not from geology, but from physics.
As noted above, the papers produced by William Thomson between 1861 and 1866 made
passing references to Darwin but did not focus their arguments on refuting Darwin's
notions. When Jenkin's article appeared, no one had yet explicitly linked thermodynamics
and Thomson's arguments on the ages of the sun and the earth to a specific criticism of
natural selection.87
The essence of the Jenkin-Thomson complaint was that uniformitarian geology
contravened not only the laws of thermodynamics, but even those of common sense, by
positing the earth as a perpetual-motion machine. To physicists and engineers, it was an
abuse of science
to suppose, as Lyell ... has done, that the substances [inside the earth], combining together, may
be again separated electrolytically by thermo-electriccurrents, due to the heat generated by their
combination, and thus the chemical action and its heat continued in an endless cycle.88
Jenkin sought to demonstrate the wrong-headedness of this notion, and to replace it
with a proper understanding of the conservation and the dissipation of energy.
We have experimentallyproved ... that the total quantity of energy in the universeis constant ... At
first sight, this constancy, in virtue of which no energy is ever lost, but simply transferredfrom
mass to mass, might seem to favour the notion of a possible eternity of change, in which the earlier
and later states of the universe would differ in no essential feature... To professor Sir
W. Thomson of Glasgow we owe the demonstration of the fallacy of this conception, and the
establishment of the contrarydoctrine of a continual dissipation of energy, by which the available
power to produce change ... diminishes at every change of the distribution of energy.89
The invocation of Thomson's name in this argument was, of course, correct, but it
served also as a clever strategy. When Jenkin's article appeared, Thomson's public fame
was at a new height: in recognition of his achievements regarding science generally and the
transatlantic telegraph cable in particular, Thomson had been knighted just eight months
earlier. To have 'Professor Sir W. Thomson of Glasgow' as an ally strengthened the
authority of an anonymous author seeking to persuade a general audience. Moreover, for
86 Jenkin, NBR, op. cit. (1), 291. Modern readers,finding Jenkin's story racist, might consider it in the context
of language common in his era. The Times story on the Alma, for example, in describing how some 200 native
crewmen and 200 European passengers and crew got safely off the sinking ship, boasted that 'the Anglo-Saxon
race again proved that pre-eminencein courage and determination which have won for them a moral superiority
over the whole world'. The Times, op. cit. (83).
87 Smith and Wise, op. cit. (13), 580.
88 Thomson, op. cit. (57), 3.
89 Jenkin, NBR, op. cit. (1), 297-98.
334
Susan W. Morris
the uniformitarians reading his essay, Jenkin's sympathetic tone ('at first sight this
constancy... might seem to favour' a uniformitarianinterpretation), introduced an air of
moderation in striking contrast to Thomson's recent scorn.
Jenkin then embarked with his readers on an extended discussion of friction, energy
conservation, and entropy, 'providing one of the most lucid explanations of the energy
doctrines given at the time'.90 Revealing the teacherhe would one day become, he carefully
explained physical science for the untrained reader, patiently returningto each point time
and again, with example upon example, in a spiralling argument illustrating the
consequences of thermodynamics on the geological premisses of natural selection. In
particular, he showed that thermodynamics applied as much to Nature as to man-made
objects.
Natureno moreworkswithoutfrictionthanwe can,andfrictionentailsa loss of availablepower
in all cases.Whenthe rainfalls,it feelsthefrictionas muchas dropsfromHero'sfountain;when
thetiderollsroundthe worldit rubsuponthesea-floor...whenthe breezeplaysamongtheleaves,
frictionoccurs...No finiteconstructionof physicalmaterialscan continueto do work for an
infinite time.91
Moreover, what applied to the earth applied equally to the solar system. Jenkin explained
to his readers that while energy as a whole was conserved, its ability to do work was not.
The transfer or redistribution of energy from one body (such as the sun) to another (such
as the earth) necessarily meant a decay or loss in the energy available to do work.
When we find the sun raising huge masses of water daily from the sea to the skies, lifting yearly
endless vegetation from the earth... performingthe great bulk of the endless labour of this world
and of other worlds, so that the energy of the sun is continually being given away; then we may
say this continual work cannot go on for ever.92
Jenkin appealed to the common sense of his readers, to their intuitive grasp of the world
they experienced daily. The sun, it could be seen, had a finite life, determined by its supply
of material and the rate at which it 'gave away' its energy. There were no other known
or anticipated sources of energy for the sun. Jenkin acknowledged that the calculations
were indeed 'imperfect', but no matter how generous one made one's assumptions,
we are assured that the sun will be too cold for our or Darwin's purposes before many million
of years - a long time, but far enough from countless ages; quite similarly past countless ages are
inconceivable, inasmuch as the heat required by the sun to have allowed him to cool from time
immemorial, would be such as to [have turned] him into mere vapour.93
How long might one expect the sun to last? Repeating Thomson's most generous
calculation, made in 1861, Jenkin answered that, 'from the earth we have no very safe
calculation of past time, but the sun gives five hundred million years as the time separating
us from a condition inconsistent with life'.94 This comment that the earth 'gives no safe
calculation' differs notably from the views Thomson had developed by 1867.
90 Smith and Wise, op. cit. (13), 536.
91 Jenkin, NBR, op. cit. (1), 296-7.
92 Jenkin, NBR, op. cit. (1), 296.
93 Jenkin, NBR, op. cit. (1), 300.
94 Jenkin, NBR, op. cit. (1), 305. Jenkin had also stated the 500 million figure on p. 301, properly crediting
it to Thomson. Ruse, op. cit. (13), 223, errs when he states that Jenkin's essay gives the earth, 'a span of 20 to
400 million years, with 98 million as the most probable figure (Jenkin, 1867)'. These figures are in Thomson's
'Secular cooling' paper of 1863 (see note 57); they do not appear in Jenkin's article.
Fleeming Jenkin and The Origin of Species
335
Jenkin, of course, agreed with the theory that the earth had once been hot and was in
a process of long-term 'secular' cooling, but neither primitive heat nor the nature of the
earth's crust and core were essential to his essay. Instead, his argumenton the lapse of time
was drawn almost entirely from Thomson's work on the age of the sun's heat, the paper
which Jenkin regretted had 'had no justice done to it' at the 1861 BAAS meeting.
Returningto his lawyer-like strategy, Jenkin added, 'this reasoning concerning the sun's
heat does not depend on any one special fact, or sets of facts, about heat, but is ... the very
essential condition of action'.95 In other words, it was not a hypothetical conjecture but
a conclusion deduced from physical principles, from laws. Then, attending again to the
mistaken beliefs of those such as Lyell, Jenkin added,
Thereis a kindof vagueidea... that somehowchemistryor electricity,&c., mayreverseall [the
coolingof the earth];but it has beenexplainedthat everyone of theseagenciesis subjectto the
samelaw; theycannevertwiceproducethe samechangein its entirety.Everychangeis a decay.96
Finally, in a passage particularly noticed by some Darwinians, Jenkin explained to his
readers what this implied for any self-contained system (such as the solar system or, more
specifically, the earth):
[Whentherehas]beena gradualandcontinualdissipationof energy,therewill on the wholehave
beena gradualdecreasein the violenceor rapidityof all physicalchanges... Thereareperiodsof
greaterandless activity,but the activityon the wholediminishes.Evenso mustit havebeen,and
so will it be, with our earth... As the sun's heat diminishes,so will the violenceof storms;as
inequalitiesof surfacediminish,so will the variationof climate.97
This gradual running down and cooling of the earth meant that there was a finite period
of time in which the earth had been, and would continue to be, hospitable to life.
Jenkin had expressed the thermodynamicists'thesis with unsurpassed clarity, bringing
it alive for his readers in a way that Thomson never accomplished. Where Thomson was
arrogant, Jenkin was humorous.98 While Thomson drew his arguments from Fourier
analysis with differentialequations, Jenkin drew from rainfall and ball games. The lyricism
of Jenkin's writing stands in marked contrast to the wooden prose of Thomson. Jenkin's
review is distinguished by its appeal to the educated but technically untrained public - the
rapidly expanding audience for the Victorian reviews.
Since the 1830s geology had enjoyed an unrivalled popularity with the public. 'The
general middle-class public purchases five copies of an expensive work on geology for one
of the most popular novels of the time',99 and most often that work on geology was Lyell's
Principles. Focusing on geological time, therefore, Jenkin's essay was assured of a keen
9S Jenkin, NBR, op. cit. (1), 300.
96 Jenkin, NBR, op. cit. (1), 300.
97 Jenkin, NBR, op. cit. (1), 302.
98 An example of Thomson's arrogance is displayed in his 1862 paper 'On the rigidity of the earth' where,
after referringto G. B. Airy as a 'naturalist' Thomson sneered in a footnote, "'Naturalist: A person well versed
in Natural Philosophy." - Johnson's Dictionary. Armed with this authority, chemists, electricians, astronomers,
and mathematiciansmay surely claim to be admitted along with merely descriptive investigators of nature to the
honourable and convenient title of Naturalist.' Philosophical Transactionsof the Royal Society of London (1863),
153, 573-82, on 577.
99 H. Martineau, History of the Peace, Boston, 1866, iii, 185.
336
Susan W. Morris
audience, a point recognized by David Douglas, the North British editor, when he placed
the critique prominently at the opening of the June issue. Jenkin struck with force against
geology because he sharedwith Thomson the view that unlimitedtime was the mortal flaw
of natural selection. In seeking to persuade and enlighten the wider public, though, Jenkin
seems inadvertently to have enlightened Darwin.
In his fourth section, Jenkin addressed his question about the extent to which the
difficulty of classifying species justified a theory of a common ancestor. Evolution by
continual modification implies a constant blurring of the boundaries defining species and
varieties.100Jenkin attempted to show that phenomena with blurry boundaries are a
common feature of both the natural and man-made worlds, and imply nothing about the
antecedents of the phenomena. His specific argumentis not especially convincing, and was
soundly attacked by Wallace a few months later,0'?but Jenkin's approach- challenging
the philosophical validity of an aspect of Darwin's theory - prepared the ground for
Jenkin's final assault on natural selection.
In his fifth and summary section, Jenkin echoed the complaint made by so many others,
and which underlay the whole of his essay.
The chief arguments
... rest on conjecture.Beasts may have varied; variationsmay have
... We are askedto believeall these maybe's
accumulated;they may have becomepermanent
happeningon an enormousscale,in orderthat we may believethe finalDarwinian'maybe,'as
to the originof species... Thereis little directevidencethat any of thesemaybe'sactuallyhave
been.'02
His scepticism shows in the 'we are asked to believe'. Rather than opposing natural
selection because it was irreligious, Jenkin's reasoning in the essay shows that he opposed
Darwin's theory at least in part because he found it too much like religion. One was
expected to receive it as one did religious dogma - by faith. Indeed, if Jenkin shared the
religious misgivings of his friend Thomson and others who opposed natural selection
because, for example, its randomness allowed no place for God, it is nowhere evident in
his essay.103 Throughout the review, he pejoratively invoked religious language, referring
to Darwin's supporters as 'true believers' and 'the faithful'. In one telling passage he
complained that 'the believer ... can marshal hosts of... imaginary foes; he can call up
continents, floods, and peculiar atmospheres; he can dry up oceans 'l04 - what was this if
not making Darwin an analogue of Moses?
This passage was marked by Darwin with the words 'good sneers', showing that
Darwin himself recognized and appreciated Jenkin's humour, a facet of the review often
seemingly lost on earnest historians of science. The ubiquitous humour of the essay
demonstrates its appeal to a general audience and the extent to which Jenkin was conscious
of writing for that audience.
100 The point is made, for example, in D. L. Hull, 'Certainty and circularity in evolutionary taxonomy',
Evolution (1967), 21, 174-89, on 175.
101 Wallace, op. cit. (23), 295.
102 Jenkin, NBR, op. cit. (1), 313.
103 Alvar Ellegard,Darwin and the GeneralReader, Chicago and London, 1990, Hull, op. cit. (1), and Moore,
op. cit. (13), contain helpful discussions of the religious objections to Darwinism.
104 Jenkin, NBR, op. cit. (1), 293.
Fleeming Jenkin and The Origin of Species
THE DARWINIAN
337
REACTION
Jenkin's anonymous review generatedimmediate interest in Darwin's circle. Joseph Dalton
Hooker lamented that he had 'been reading Tate's? [sic] Review in N. British, & wish I
was not so confounded lazy and I would answer it'.'05 Other Darwinians sniffed that the
critique was 'pretentious' and it was 'a pity the man who wrote it had not studied a little
zoology and botany before writing about them'.106
Darwin appears to have taken the review seriously from the start. Most noteworthy is
that almost immediately upon reading it he wrote to Lyell, saying he would be in London
the following week and wanted to discuss the article with him.'07Next, Darwin answered
a letter from Charles Kingsley, replying that the piece 'seems to me one of the most telling
Reviews of the hostile kind'.'08
In a letter to Darwin on 6 June 1867, Kingsley had called to Darwin's notice a particular
part of the essay,
I advise you to look at a wonderfularticle in the North Britishabout you... Remarkthe
argument... thatgeologicalchangesweremoreviolent,& the physicalenergiesof the earthmore
intensein old times... if thatbe true- thenchangesof circumstances
in plantsand animalsmust
have beenmorerapid.'09
Clearly, Kingsley's interest in the article was in its attack on uniformitarianismand on
geological time, and he recognized that Jenkin's criticisms contained not only a statement
of the problem, but also the mechanism of its solution. In his reply on 10 June, Darwin
planted the review in this identical soil of geological time:
With respectto the antiquityof the world & the uniformityof its changes,I cannotimplicitly
believethemathematicians,
& Thompson
seeingwhatwidelydifferentresultsHaughton/Hopkins
[sic] havearrivedat. By the way I had a notefromLyellthis mg. who doesnot seemto valuethis
articleenough.Is therenot greatdoubton the bearingof the attractionof gravitywith respect
to the conservationof energy?The glacialperiodmaymakeone doubtwhetherthe temperature
of the universeis so simplea question.110
Darwin's protest about not believing the 'mathematicians' shows what had, over the
years, become his almost reflexive response to the criticisms of physicists and
astronomers."' As we have seen, Darwin had disdained Thomson's repeated attacks on
geological time, and deleted his erroneous Weald argument, for example, because of
complaints from geologists, showing no concern over the criticisms of physicists.
In this letter to Kingsley, however, we can see Darwin grappling, for the first time, with
the physical arguments. Clearly he does not accept Jenkin's views. Indeed, to accept them
would have meant surrenderinghis gradualist theory. Even adopting the view urged by
105 J. D. Hooker to Darwin, 18 June 1867, DAR 102: 167-8. 'Tate' refers to Peter Guthrie Tait, who was
known to contribute to the North British Review.
106 Wallace to Darwin, 25 September 1867, DAR 106/7; Charles Kingsley to Darwin, 6 June 1867, DAR 169.
107 Darwin to Lyell, 9 June 1867, American Philosophical Society (APS), 329.
108 Darwin to Charles Kingsley, 10 June 1867, APS 330.
109 Kingsley to Darwin, 6 June 1867, DAR 169.
110 Darwin to Kingsley, op. cit. (108).
111 Darwin undoubtedly refers not to 'mathematicians' per se, but to practitioners of the school of
' mathematical geology', of which William Hopkins had been a founder. See Smith, op. cit. (45).
338
Susan W. Morris
Kingsley, that changes had been more rapid in the past and that evolution might thus have
proceeded more quickly, meant retreating from uniformitariangeology, and that was a
step Darwin resolutely refused, adamantly replying to Kingsley, 'the crust of the earth was
at this recent period as now, & the force of Nature not more energetic'."' But Darwin's
bluster in this letter, and the compass of his protests, attest to a new anxiety.
In these two immediate reactions to the article, writing to Lyell and to Kingsley, it is
plain that Darwin's attention was seized neither by the nature of variations, nor by the
mechanismof inheritance.He focused on Jenkin's argumenton geological time. We should
note Darwin's comment to Kingsley that Lyell does not value the article highly enough. In
what context would Lyell have valued the article at all, if not in terms of the attacks Jenkin
had launched against uniformitariangeology?
Darwin's letter to Kingsley is equally revealing, however, for the light it sheds on the
lingering issue of Jenkin's influence on the subject of variations, for Darwin remarks that
Jenkin's review had helped him realize he must change some of his wording in the Origin.
He writes that one portion of the review,
whichcould makeme modifywordingof a few passagesin the Originis I thinkaboutsudden
sports,& these I have alwaysthought,but now moreclearlysee, would generallybe lost by
crossing.R[eviewer].does not howevernotice,that any variationwould be morelikelyto recur
in crossedoffspringstill exposedto sameconditions,as those whichfirstcausedthe parentto
vary...I havemoreoverexactlystatedthat I do not believein the suddendeviationof structure,
undernaturesuchas occursunderdomestication,butI weakenedthe insistance[sic] in deference
to Harvey.113
Certainly, the phrase 'but now more clearly see' is susceptible to the traditional
interpretation that only from reading Jenkin did Darwin come to realize that saltations
would be swamped by large numbers of unvaried organisms. But the passage taken as a
whole argues against this interpretation.Darwin states plainly enough that 'I have always
thought' that saltations would be lost by swamping, while his last sentence implies that he
recognizes his error in weakening his insistence against sports, because the weakening has
resulted in readers, such as Jenkin, misunderstandinghis views.
In other words, Darwin seems to have seen, from Jenkin's having misunderstood him,
that readers inferred that Darwinian evolution might proceed by saltations. His
exasperation with the misunderstanding is vividly conveyed by his indignant 'I have
moreover exactly stated', and his real view is clearly put forward: 'I do not believe in the
sudden deviation of structure.' Overall, the passage supports the conclusion, originally
stated by Vorzimmer, that Darwin did not form his opinions on variations and inheritance
as a consequence of reading Jenkin, but did so long before.
What is it, then, that Jenkin helped Darwin 'more clearly see'? We can only conjecture,
but it may be that Darwin recognized in Jenkin's mathematical example an explanation
that would be effective in communicating to readers the very point Darwin had always
112 This quote is from a draft (DAR 96: 9, 32) of Darwin's letter of 10 June. One sheet (of four) of the finished
letter (op. cit. (108)) is lost, but the extant draft is complete. I thank the Darwin Project, Cambridge University,
for providing a transcriptof the draft. Since we do not know that the completed letter was identical to the draft,
it is probably more appropriate to take the draft as revealing Darwin's immediate reaction to Jenkin's essay.
113 Darwin, op. cit. (112).
Fleeming Jenkin and The Origin of Species
339
held. In other words, Jenkin and Darwin agreed on the problem with sports, and in arguing
against them Jenkin created an argument that Darwin could borrow (which, indeed, he
did) to make his own view more clear. Realizing now that he must strengthen his
'insistence' against saltations, Darwin goes on in his letter to Kingsley to give an example
of how he would amend his wording in the Origin.
Whenspeakingof the formationfor instanceof a new speciesof Birdwith long beak,Insteadof
saying,as I haveup to now incautiouslydone,a birdsuddenlyappearedwith a beakbeinglonger
thanthatof his fellows,I wouldnow saythatof all the birdsannuallyborn,somewill havea beak
a shadelonger,& some a shadeshorter,& that underconditionsor habitsof life favouringa
longerbeak,all the individuals,withbeaksa littlelongerwouldbe moreaptto survivethanthose
with beaks shorter than average.114
Wording that had heretofore seemed to refer to saltations - 'a bird suddenly appeared'
- would henceforth be changed to make plain that Darwin was all the time referringto
individual differences. It seems clear, then, that Jenkin's influence in the matter of
variations was limited to changing the style in which Darwin expressed his ideas, not in
changing the ideas themselves.
For the next few months, Darwin's extant correspondence shows few signs of anxiety
over the age of the earth. In a letter to Lyell, however, Darwin suddenly thanked Lyell 'for
your long and interesting letter ... You give me some consolation but I take the Sun much
to heart.'115 The tone and wording of Darwin's letter suggest that the problem had
weighed on his mind for awhile. 'The Sun' was, of course, Thomson's argument from
1861, which Darwin had never, in the interveningyears, either explicitly acknowledged or
even apparently recognized as an obstacle for his theory. Yet now, we see that a major
transformation had occurred in Darwin's views.
Historians have inferredthis letter of Darwin's to have been written in early March 1868,
and to have been provoked by William Thomson's paper, 'On Geologic Time', read on
27 February1868 to the Geological Society of Glasgow. It seems unlikely, however, that
there was sufficient time after the delivery of Thomson's address for Darwin to have
written such a letter.116
More telling, however, is that the purpose of Thomson's Glasgow paper was to present
new arguments regardingthe influence of the tides on geological time. The cooling of the
earth occupied a decidedly secondaryportion of the paper, and the sun's heat an even more
minor third portion. Furthermore,in these sections on the earth and on the sun, Thomson
114 Darwin, Draft letter, op. cit. (112).
115 Darwin to Lyell, APS 346; see also T. Carroll (ed.), An Annotated Calendar of the Letters of Charles
Darwin in the Library of the American Philosophical Society, Wilmington, Del., 1976, 129.
116 By its return address, scholars in the Darwin Project know that the letter was written during one of three
time periods: September 1867, 1-10 March 1868, or September 1868. The March date has been privileged on the
assumption that the letter was provoked by Thomson's paper, read on the evening of 27 February 1868. This
assumption seems unlikely, in that it requiresthat Darwin, in London, acquire an actual copy of Thomson's paper
from Glasgow, digest the contents of that lengthy, technical paper, confess his worry to Lyell, and then that Lyell
develop and write a 'long letter' addressing Thomson's arguments, all in the few days allowed by the March
dates. Moreover, one page of Lyell's letter was not mailed with the rest, making it incomprehensibleto Darwin
until he received the missing sheet. The time requiredfor all this would seem to render improbablethat Darwin's
letter, if written in March, was caused by Thomson's address. September 1868 is unlikely for other reasons not
germane to this paper.
340
Susan W. Morris
added nothing new to the arguments he had advanced in 1861, arguments Darwin had
heretofore ignored. It is difficult to understand, therefore, why or how this paper alone
would suddenly have caused Darwin to reverse himself and take the sun, especially - not
the tides and not the earth - 'much to heart'.
However, if we look again at Jenkin's paper, we find a lapse-of-time argument based
entirely on the dissipation of the sun's heat, and which might therefore be considered a
more credible cause of Darwin's newly evinced concern. If so, then it is possible that the
letter to Lyell was written as early as September 1867.
Lyell was not the only one with whom Darwin discussed his growing concern about the
shortness of time. At the Norwich meeting of the British Association in August 1868,
Joseph Dalton Hooker, as President, used part of his Presidential Address to review
Darwin's contributions to science. In preparinghis speech, he engaged Darwin's assistance,
both in correspondenceand in a personal visit shortly before Hooker went to Norwich."17
It seems safe to assume, therefore, that Hooker's address was consistent with Darwin's
own thinking. It is significant, in this regard, that Hooker directed fully half of his remarks
about Darwin's work to defending the Origin against the criticisms regarding the age of
the earth, specifically as raised by Jenkin. The astronomers' objections to Darwin's
theories, Hooker began, 'are strenuously urged in what is in my opinion the cleverest
critique [of Darwin's work] that I have hitherto met with'. He then went on to describe
the shortness of time as the 'most formidable argument urged by the reviewer'.18 We
might see Hooker's address, therefore, as a succinct Darwinian assessment of Jenkin's
essay. Hooker's analysis concurs with Darwin's later statements attesting to the essay's
value, and identifies Jenkin's crucial argument as that regarding the age of the earth, not
the arguments on variations and inheritance.
Searching for a solution to the dilemma of geological time Darwin turned, in 1868, to
his son, George, a newly-minted Cambridgewrangler, and to James Croll, for assistance.119
From George, he sought help in comprehending Thomson's work. From Croll, he hoped
to gain not only comprehension, but a counter-argument.
It is curious that Darwin should have turned to Croll. Self-educated and antiuniformitarian, Croll considered himself closer to physics than to geology. Moreover,
Croll's own estimates of the age of the earth were even more restrictive than Thomson's.
In an earlier day, Darwin would perhaps have lumped him with 'Hopkins, Hennessey,
Haughton, and Thomson' as one of those mathematicians who should be ignored. That
Darwin now looked to him for help suggests the extent of the change in Darwin's
perception of his predicament. Croll helped Darwin come to terms with the validity of the
physical arguments against natural selection, and persuaded him to reject the false physical
concepts to which he clung in hopes that they might mitigate the Thomsonian arguments
117 See Hooker to Darwin, 22 June, 12, 25 and 29 July and 6 August 1868; Darwin to Hooker, 6 June, 14,
17 and 28 July and 17 August. The 17 August letter notes Hooker's visit to Down. Hooker's letters are in DAR
102, Darwin's in DAR 94.
118 J. D. Hooker, 'Address of Joseph D. Hooker, President', Report of the 28th Meeting of the British
Association for the Advancement of Science, Norwich, August 1868, London, 1869, pp. lxxi-lxxii.
119 See, for example, Charles Darwin to George Darwin, 9 December 1868, DAR 210.1.1; George Darwin to
Charles Darwin, 6 February1869 and 14 February1869, DAR 210.2, which discuss Darwin's concerns regarding
the age of the earth.
Fleeming Jenkin and The Origin of Species
341
so clearly advanced by Jenkin. In February of 1869, for example, Croll confirmed the
certitude of Jenkin's argument on dissipation,
It is a pity that Sir Charles [Lyell] should have made those remarkson the secular loss of heat... If
there is one thing more than any other in physics, regarding which we have absolute certainty,
it is that the solar system is losing its store of energy. We not only know this fact, but we have
a means of determining the actual rate at which it is losing its power.120
Croll supported Thomson's estimate of 100 million years for the age of the earth; he had
himself arrived at the figure of 60 million years. But, after reading Darwin's admission
that he was 'greatly troubled at the short duration of the world', Croll responded
encouragingly that, 'it is quite possible that we may yet be able to get considerably more
than one hundred million of years, although very much beyond this we are brought to a
limit by other considerations. 121 He also assured Darwin that 'I think that you may quite
fairly assume a very long period before the Cambrian formation, even according to Sir
William Thomson's theory."'
Darwin entertained the hope that electromagnetic phenomena might affect the energy
content and, consequently, the age, of the earth, and Croll addressed this as well:
One thing is certain, that it is but an infinitesimal quantity of the forces of nature that ever
assumes the electric or magnetic form ... The quantity of energy in the form of electricity coming
from the sun (if there be any at all) is certainly trifling compared with what comes in the form
of heat.123
While Darwin incorporated some of Croll's ideas into the Origin, he could do little to
respond to arguments that were, essentially, unanswerable,124 except by shortening the
time required for natural selection to work.
Over the succeeding months, Darwin came to believe that 'negative selection', the
increased destruction of non-adapted creatures, would not only help overcome the problem
of swamping but, more important, would accelerate the evolutionary process. Negative
selection consequently became more prominent in the later editions of the Origin. We see
this change in Darwin's thinking most clearly if we look back at Darwin's explanation to
Kingsley, in June 1867, of how he would modify his wording in describing variation and
selection. Darwin had then written,
I would now say that of all the birds annually born, some will have a beak a shade longer, & some
a shade shorter, & that under condition or habits of life favouring a longer beak, all the
individuals, with beaks a little longer would be more apt to survive than those with beaks shorter
than average.
Eighteen months later, however, for the fifth (1869) edition of the Origin, Darwin had
altered his example, from an emphasis on increased survival to one on increased
destruction:
If... a bird of some kind could procure its food more easily by having its beak curved, and if one
were born with its beak strongly curved, and which consequently flourished, [from this would
120 Croll to Darwin, 4 February 1869, DAR 161.
121 Darwin to Croll, 31 January 1869, APS 361. Reprinted in J. C. Irons Autobiographical Sketch of James
Croll, with Memoir of his Life and Work, London, 1896, 216. Croll to Darwin, 4 February 1869, DAR 161.
122 Croll to Darwin, 4 February 1869, DAR 161.
123 Croll to Darwin, 4 February, DAR 161.
124 See Burchfield, op. cit. (5), for an exposition of Darwin's response.
342
Susan W. Morris
follow] the preservationof a large numberof individualswith... curved beaks, and... the
destructionof a still largernumberwith the straightestbeaks.125
The element of increased destruction of the original creatures appeared to solve the
problem of swamping. More necessaryfor Darwin, however, was that it shortened the time
requiredfor a variant organism to become successful. And by the time Darwin introduced
this change to the Origin, shortening the time had become of paramount importance. This
one idea, therefore, simultaneously helped solve two of the problems raised by Jenkin:
swamping by large numbers, and the short age of the earth. Many scholars have noted this,
but seem to have missed its full value in terms of time.
In general, the modifications that Darwin introduced to his theory - the increased
reliance on sexual selection, on the inheritance of acquired characteristics,and on other
mechanismsof evolution - which have for so long intriguedscholars, have been interpreted
by them largely as solutions to problems of swamping and blending. Scholars have
occasionally noted that these mechanisms would also accelerate the rate of evolutionary
change, without explicitly recognizing that speeding up the process was Darwin's most
urgent need. Inheritance was no longer his crucial problem. Vorzimmer shows us that
Darwin had, to his own satisfaction, solved the inheritanceproblem. If we look, therefore,
through Darwin's eyes, rather than through a lens crafted by Mendelism, the crucial issue
facing Darwin when he sat down to revise the Origin was the shortness of time. As he
wrote to Wallace in December 1869, 'if you throw light on the want of geological time,
may honour, eternal glory and blessings crowd thick on your head'.126
When it came to grappling with the age of the earth, however, Darwin himself could
only introduce to the Origin (1869) the rueful admission that,
Herewe encountera formidableobjection;for it seemsdoubtfulwhetherthe earthin a fit state
for the habitationof livingcreatureshas lastedlongenough... Mr. Crollestimatesthat about60
millionyearshaveelapsedsincethe Cambrianperiod,but this... seemsa veryshorttimefor the
many and great mutations of life.127
Darwin then took refuge in a restatement of the argumenthe had read in Thomson and
in Jenkin, the argumentHooker had also noted in his BAASAddress,and that Kingsleyhad
called to Darwin's attention immediately after readingJenkin's review - the argumentthat
comprised the main thermodynamicalobjection to uniformitarianism.In the end, Darwin
made a concession, small, but a concession none the less:
It is, however, probable, as Sir William Thompson [sic] insists, that the world at a very early
period was subjected to more rapid and violent changes in its physical conditions than those now
occurring; and such changes would have tended to induce changes at a corresponding rate in the
organisms which then existed.128
125 Darwin, op. cit. (11), 178-9.
126 Darwin to Wallace, 5 December 1869, reprintedin Alfred Russel Wallace: Lettersand Reminiscences (ed.
James Marchant), New York and London reprint edn, 1975, 204. Darwin was replying to a letter from Wallace
in which Wallace had announced, 'I have written a paper on Geological Time, which will appear in Nature, and
I think I have hit upon a solution of your greatest difficultiesin that matter'. Wallace to Darwin, 4 December 1869,
ibid., 204.
127 Darwin, op. cit. (11), 513. Note Darwin's expression 'great mutations of life' when he appears to mean
'individual differences' or its alternative,'insensible variations', as an example of how his wording could confuse
readers.
128 Darwin, op. cit. (11), 513.
Fleeming Jenkin and The Origin of Species
343
Darwin's attribution of this point to Thomson is, of course, correct, but also
noteworthy. While the arguments on the shortness of time were, indeed, created by
Thomson, it appears to have been Jenkin who articulated them with sufficient grace and
clarity to convince Darwin of their importance.When Thomson advancedthese arguments,
Darwin paid no heed. Only after he read Jenkin's review - immediately after reading it had Darwin become concerned about the problem of 'lapse-of-time'.
CONCLUSION
Historians have followed customary practice in attributing to Sir William Thomson the
arguments on the shortness of geological time. This custom, however, has masked the role
of Fleeming Jenkin in translating Thomson's arguments such that Darwin finally came to
realize that those argumentsimperilledhis theory of natural selection. Jenkin's advocating
them in a journal aimed at the general public further imperilled the serious influence that
Darwinian theory was just beginning to command in public opinion.
The ultimate reasons for this sequence of events may lie as much in the audiences for
science as in the science itself. In contrast to Thomson's formal and highly technical
arguments aimed largeiy at other scientists, Jenkin's writings aimed at basic, thorough
instruction of the rapidly growing, literate public, a public especially eager to understand
and make informed judgementson the latest developments in science and technology. Both
Jenkin's review and Darwin's Origin of Species were directed at that same audience.
Reared in four countries, travelling around the globe in cable-laying expeditions, and
frequenting the drawing-rooms of novelists and politicians, Jenkin had grown adept at
mediating between cultures. Writing for the readers of the Victorian reviews was for him
an opportunity to dramatizeissues of compelling importanceto contemporaryreaders,and
to translate between the technical and non-technical worlds, irritating and educating the
inhabitants of both. His essays brought new and singular argumentsto bear on previously
well-discussed topics. His disputatiousnesswould not let him rest when an argumentcould
be had. His innovative and theatrical imagery impressed his ideas vividly on the minds of
his readers. All his essays in the North British Review share these essential qualities of
translation, provocation, and melodrama.129In the Origin review, his most well known, he
transformed the alien language of mathematics and the new science of thermodynamics
into a vernacular comprehensible to an intelligent but non-mathematical audience, one
member of which turned out to be Charles Darwin.
129 F. Jenkin, 'Submarinetelegraphy' NBR (December 1866); 'The origin of species' (June 1867); 'Fecundity,
fertility, and sterility' (December1867); 'Trade-unions: how far legitimate' and 'The atomic theory of Lucretius'
(both in March 1868).
15
BJH 27